SUBTITLE 151 CHAPTER. Ratios & Proportions

Transcription

1 SUBTITLE 151 CHAPTER Ratios & Proportions

2 152 CHAPTER 3 RATIOS AND PROPORTIONS Section 3.1 Ratios and Proportions Ratios are used to compare the number of objects in two or more groups. The teacher has 3 students. We write the ratio as 1 teacher to 3 students 1 teacher : 3 students Order is important in ratios. EXAMPLE Write the ratios. (a) The ratio of teachers to students is 1 : 6 But the ratio of students to teachers is 6 : 1 (b) The ratio of cakes to candles is 1 : 8 The ratio of candles to cakes is 8 : 1 MATHEMATICS FOUNDATION 1

3 RATIOS AND FRACTIONS 153 Practice 1 Write the ratios. The ratio of adults to children is. The ratio of to is 3 : 2. The ratio of to is 1 : 4. The ratio of people : keys is.. Ratios are not the same as fractions but they do share some of their properties with fractions. Equivalent fractions are equal in value. 1 Unit We can see = = We usually write fractions in their simplest form. Which of the fractions is in simplest form? To check if two fractions are equivalent we cross multiply. The fractions are equivalent if the answers are equal.

4 154 CHAPTER 3 RATIOS AND PROPORTIONS EXAMPLE (a) Are the fractions equivalent? 1 3 and 2 6 Cross multiply = 6 The answers are equal. 2 3 = 6 Yes, the fractions are equivalent. (b) Are the fractions equivalent? 1 3 and 4 10 Cross multiply = 10 The answers are not equal. 3 4 = 12 No, the fractions are not equivalent. Practice 2 Are the fractions equivalent? (a) Yes No Circle the correct answer. 2 6 and 3 9 (b) Yes No Circle the correct answer. 9 2 and 10 7 (c) Yes No Circle the correct answer and 8 24 (d) Yes No Circle the correct answer and MATHEMATICS FOUNDATION 1

5 EQUIVALENT RATIOS 155 Practice 3 (e) Yes No Circle the correct answer and (f) Yes No Circle the correct answer and Like fractions, ratios can also be equivalent. When they are equivalent, we say the ratios are in proportion. EXAMPLE Write two more equivalent ratios for the ratio given. (a) teachers to students 1 : 3 = 2 : 6 = 3 : 9 (b) boys to girls 2 : 3 = 4 : 6 = 6 : 9

6 156 CHAPTER 3 RATIOS AND PROPORTIONS Practice 4 Write two more equivalent ratios for the ratio given. (a) motorcycles to passengers 1 : 2 = = (b) moons to stars 1 : 5 = = (c) supervisors to employees 1 : 10 = = MATHEMATICS FOUNDATION 1

7 EQUIVALENT RATIOS 157 We sometimes write ratios in fraction form to help us with calculations. 2 : The second number becomes the denominator. EXAMPLE Are the ratios equivalent (in proportion)? (a) 1 : 5 and 3 : 15 Write the ratios 1 3 in fraction form. and 5 15 Cross-multiply 1 15 = 15 and 5 3 = 15 The answers are equal. Yes. The ratios are equivalent. Practice 4 Are the ratios equivalent (in proportion)? (a) 2 : 3 and 6 : 9 (b) 3 : 10 and 1 : 5 (c) 1 : 4 and 3 : 10 (d) 21 : 56 and 15: 40

8 158 CHAPTER 3 RATIOS AND PROPORTIONS Section 3.1 Exercises 1. Complete the following. (a) (b) The ratio of printers to computers is : The ratio of computers to printers is :. dartboard darts (c) (d) The ratio of darts to dartboards is :. The ratio of to is 1 : 3. (e) (f) The ratio of is 4 to 3. The ratio of is 3 to 4. (g) (h) The ratio of is 3 : 1 The ratio of is 1 : 3 MATHEMATICS FOUNDATION 1

9 EXERCISES Are the fractions equivalent? (a) Yes No Circle the correct answer and (b) Yes No Circle the correct answer and Write two more equivalent ratios for the ratio given. (a) nurses to babies 1 : 3 : : (b) Carrots to rabbits 4 : 1 : : 4. Are the ratios equivalent? (a) 4 : 6 and 10 : 15 (b) 8 : 12 and 14 : 21 (c) 21 : 30 and 2 : 3 (d) 9 : 32 and 2 : 7

10 160 CHAPTER 3 RATIOS AND PROPORTIONS Practice 1 5. Look at the ratio on the left. Circle the ratios on the right that are equivalent to the given ratio. (a) 2 : 3 4 : 6 5: 7 6 : 9 (b) 1 : 2 2 : 3 2 : 4 3 : 6 (c) 2 : 5 3 : 5 4 : 8 4 : 10 (d) 1 : 3 2 : 6 3 : 8 10 : 30 MATHEMATICS FOUNDATION 1

11 SIMPLIFY RATIOS 161 Section 3.2 Unit Ratios and Rates These ratios are all the same in proportion: 80 : : : : 5 2 : 1 (simplest form) Always write the ratio as simply as possible. This is called the simplest form. The simplest form of a ratio means that all the numbers in the ratio must be whole numbers and that all the numbers in the ratio cannot be divided by the same number (except 1). EXAMPLE Write the following as ratios in their simplest form. (a) 30 to : 40 divide both terms by 10 = 3 : 4 (b) 18 to 6 18 : 6 divide both terms by 6 = 3 : 1

12 162 CHAPTER 3 RATIOS AND PROPORTIONS You can simplify ratios with two terms using the a b key on a calculator. c You cannot simplify ratios with more than two terms using the a b key. c 30 (a) 30 : 40 = 40 key: 30 a b 40 = display 3 4 c The ratio is b) 18 : 6 = or 3 : 4 key: 18 a b 6 = display 3 c The ratio is not 3. It is 3 to 1 or 25 (c) 25 : 15 = or 3 : 1 key: 25 a b 15 = display c Use the shift key to convert this to an improper fraction. key: shift a b display 5 3 c The ratio is 5 : 3 Using a calculator to simplify ratios only works when the ratio compares two numbers. and then simplify them. EXAMPLE Write the following as ratios in their simplest form. (a) 2.4 to has one digit after the decimal. Multiply it by 10 to change it to a whole number. You must also multiply all other terms of the ratio by the same number in order not to change the value of the ratio. 2.4 : 10 multiply by : 100 divide by 4 6 : 25 Most calculators can simplify a decimal ratio of two terms without having to multiply by 10. key: 2.4 a b 10 = display 0.24 c a b display: 6 25 c

13 SIMPLIFY RATIOS 163 (b) 0.63 to : 1.8 multiply by : 180 divide by 9 7 : 20 Or, key: 0.63 a b 1.8 = display 0.35 c display 7 20 a b c (c) 1 to Multiply the denominators together: 3 4 = 12 Now, multiply both terms in the ratio by : 1 1 multiply by = 4 : 15 the ratio cannot simplify any further Or, key: 1 a b 3 1 b c a 1 b c a 4 = c display: 4 15 You cannot simplify a ratio with three or more terms using the key. (d) 24 to 40 to : 40 : 16 divide by 8 = 3 : 5 : 2 (e) 1.25 to 3.75 to : 3.75 : 7.5 multiply by 100 = 125 : 375 : 750 divide by 125 = 1 : 3 : 6 (f) Multiply the denominators together: = : : multiply by = 56 : 21 : 36 the ratio cannot simply any further

14 164 CHAPTER 3 RATIOS AND PROPORTIONS Another way to simplify a ratio is to write it in the form 1 : n or n : 1. This is called a unit ratio. It is often more useful because it is easier to read. The surface of the earth is made up of million square kilometres of water and million square kilometres of land. The ratio of land to water is : When you write this ratio you get land : water = : This is not easy to read. If you divide both parts of the ratio by 147.1, you get land : water = 1 : 2.4 (to 1 d.p.) This is easy to read. You can now see that: The surface of the earth has almost times as much water as land. Similarly, the ratio of water to land is 2.4 : 1 Unit ratios are very important in solving some applications. EXAMPLE Write the following as unit ratios. Round your answers to 2 d.p. where necessary. (a) 7 to 20 = 1 : 2.86 divide by 7 (b) 2.4 to 10 = 1 : 4.17 divide by 2.4 (c) 12 to 5 = 2.4 : 1 divide by the smaller number 5 (d) 0.68 to 2.73 to 1.97 = 1 : 4.01 : 2.90 divide by 0.68 To change a ratio to a unit ratio, you usually divide by the smallest number. Note: (a) Write 4 : 10 in simplest terms. 4 : 10 in simplest terms is 2 : 5 (b) Write 4 : 10 as a unit ratio. 4 : 10 as a unit ratio is 1 : 2.5 Do not mix the two cases. A ratio in simplest terms is not necessarily the same as a unit ratio. A ratio in simplest terms consists of whole numbers only. MATHEMATICS FOUNDATION 1

15 RATES 165 When one amount is compared to one unit of another amount it is called a rate. A speed of 80 km per hour is a rate of travel A salary of Dh 10,000 per month is a rate of pay A typist typing 75 words per minute is a rate of typing AED per US dollar is a rate of exchange You will often see the symbol / used for per 80 km/h Dh Dh 10,000/ month 75 words/minute 75 words/minute Dh /US$ Dh /US$ So, when units in a ratio cannot be converted to the same units, the ratio is called a rate. In this case the ratio compares two different kinds of measurement. 222km A car travels 222 kilometres in 4 hours. This is a rate of. 4h The units cannot be made the same because they measure different things, but the numbers 222km = 4h 55.5km 1h So, this can be written as 55.5 kilometres per hour or 55.5 km/h. The word per means for each one. 50 km/h is called a unit rate because it compares a quantity to one unit of another. The word unit in unit rate means the number 1. EXAMPLE Express the following as unit rates. (a) 250 km to 3.5 h (to 2 d.p.) (b) Dh 55 : 20 kg = km/h = Dh/kg A ratio compares two numbers or quantities of the same kind. A rate compares two quantities of a different kind. EXAMPLE I can type 45 words per minute. How many words can I type in 20 minutes? To go from one minute to 20 minutes, you must multiply = 900 I can type 900 words in 20 minutes.

16 166 CHAPTER 3 RATIOS AND PROPORTIONS EXAMPLE How many times can 780 go into 4680? You must divide = 6 The journey will take 6 hours. EXAMPLE A car travels a distance of 415 km in 5 hours. What is the average speed of the car for the journey? You must go from 5 hours to one hour (unit rate). You must divide = 83 The average speed is 83 km/h. Section 3.2 Exercises 1 There are 20 teachers in Foundations. 12 of the teachers are men, the rest are women. Write the answers in their simplest form. (a) (b) What is the ratio of men to women? What is the ratio of women to men? m 2 is enlarged to a new area of 13 m 2. Find the 3 A car can travel 200 km on 40 L of petrol. What is the rate of consumption in km per L? Write your answers in simplest form. (a) Write this ratio in its simplest form. (c) (d) What is the ratio of tests to homework? What is the ratio of tests to the total? MATHEMATICS FOUNDATION 1

17 EXERCISES Measure the length and height of the images given below to the nearest cm. (a) Record your measurements in the given table. Small Large Image Length (cm) Height (cm) (b) (c) Find the ratio of the lengths of the small image to the large image. Find the ratio of the heights of the large image to the small image. 6 The cost for building a wall was Dh 250 for materials and Dh 150 for labour. What is the ratio, in simplest form, of the cost of materials to the total cost of labour and materials? 7 A car travels at a steady speed of 82 kilometres per hour. How long does the car take to travel 410 kilometres? 8 A lorry took 11 hours to travel 682 kilometres. What was the average speed of the lorry? 9 The distance by air from Abu Dhabi to Tokyo is 8075 km. An aeroplane can average 10 A top speed typist can type 325 words in 5 minutes. What is her maximum rate of typing in words per minute? 11 The petrol tank of a car holds 60 litres. The car can travel 12.6 km per litre. How far will the car travel on one full tank of petrol? 12 A petrol pump can deliver petrol at the rate of 0.5 L/s. How many seconds does it 13 An aircraft travelled 9152 kilmetres in 11 hours. What was the speed of the aircraft? 14 I take 3.5 hours to walk 19 km. What is my speed in km/h to 2 d.p.? 15 There are yen to 1 euro. How many yen will I get for 50 euros?

18 168 CHAPTER 3 RATIOS AND PROPORTIONS Section 3.3 Solving Proportions Sometimes one of the numbers in a proportion is not known. We want to Use a letter to represent the unknown number. Look at the ratios. n : 4 and 2 : 8 We want these ratios to be equivalent. Write n 2 = 4 8 EXAMPLE Example 1 Find the values of n that make the ratios equivalent (a) Write the ratios as fractions. Cross-multiply Divide both sides by 8 n : 4 and 2 : 8 nx8 = 4X2 nx8 = 8 nx8 = 8 n = MATHEMATICS FOUNDATION 1

19 SOLVING PROPORTIONS 169 EXAMPLE (b) 2 : 3 and n : 12 Write the ratios as fractions. 2 and n 3 12 Cross-multiply 2X12 = 3Xn 24 = 3Xn Divide both sides by 8 24 = 3 n = 8 3Xn 3 Practice 1 Find the values of n that make the ratios equivalent. (a) 4 : 5 = n : 15 (b) 1 : 7 = n : 21 (c) 1 : 7 = n : 16 (d) 3 : n = 6 : 8 (e) 2 : 5 = n : 13 (f) 8 : n = 45 : 90 (g) 34 : 28 = 20 : n (h) 60 : n = 2 : 3

20 170 CHAPTER 3 RATIOS AND PROPORTIONS We can use equivalent ratios to solve many types of word problems. EXAMPLE (a) What are the units in the ratio? You must keep the same order in all equivalent ratios. Put the information in a table and it helps you to keep the correct order. complete the table. Cross multiply. Jamal walks 3 km in 1 hour. How far can he walk in 5 hours? km h 3 1 n 5 n = 3 X 5 n is the number of km he can walk in 5 hours n = 15km Jamal can walk 15 km in 5 hours. (b) Sami buys 5 grams of gold for Dh 210. Jassim buys 7 grams at the same price per gram. How much does 7 grams of gold cost? What are the units in the ratio? g Dh n n is the cost of 7g of gold. Complete the table. Cross multiply. n X 5=7 X 210 nx5 5 7X210 = 5 Jamal can walk 15 km in 5 hours. (c) change GBP 300 to dirhams. 1 GBP = AED GBP 300 = AED Decide what are the units in the ratio. We want to change GBP to AED From the Currency Table we see 1 GBP = AED Arrange the information in a table. GBP AED n n 1 = n = n is the number of AED we get for GBP 300. MATHEMATICS FOUNDATION 1

21 WORD PROBLEMS 171 Practice 2 1. A 4-minute telephone call costs Dh How much does a 30-minute callcost? grams of gold costs Dh 430. How many grams of gold can I buy for Dh 645? 3. Four apples cost Dh 2. How much do ten apples cost? 4. 5 metres of material costs Dh 35. How much does 7 metres of material cost? 5. Ashley earns Dh 400 for 5 hours work. How much does he earn for 8 hours work?

22 172 CHAPTER 3 RATIOS AND PROPORTIONS ml (millilitres) of water is mixed with 100 g of powder to make plaster. How many millilitres of water are needed to mix with 300 g of powder? 7. Seven tents cost Dh How many tents can I buy for Dh ? 8. The scale on a map is 10 cm : 75 km. The distance between Abu Dhabi and Ras Al Khaimah is 345 km. What is the distance on the map? 9. Amna can type 63 words per minute. How many can she type in 20 seconds? (Hint: Both time periods must be in the same unit of measurement.) 10. Five trucks can carry 133 tonnes of sand. How many tonnes of sand can 8 trucks carry? MATHEMATICS FOUNDATION 1

23 WORD PROBLEMS A photocopier makes 500 copies in 8 minutes. How many copies can it make in 1 hour? 12. A kilogram of gold costs costs AED How much does 60 g of gold cost? 1 kg gold -AED There are 30 teaspoons of sugar in a 1-L bottle of Coca-Cola. How many teaspoons of sugar are there in a 330 ml can of Coca-Cola?

24 174 CHAPTER 3 RATIOS AND PROPORTIONS It is called a Currency Exchange Rate table. A Currency Exchange Rate table is like a price list in a restaurant. Currency Exchange Rates Currency Name Currency Code AED Australian dollar AUD Bahraini dinar BHD Canadian dollar CAD European Community euro EUR Hong Kong dollar HKWD Indian rupee INR Japanese yen JPY Kuwaiti dinar KWD New Zealand dollar NZD Omani riyal OMR pound sterling GBP Saudi riyal SAR Singapore dollar SGD US dollar USD MATHEMATICS FOUNDATION 1

25 WORD PROBLEMS 175 Practice 3 Use the exchange rate table to change the currencies. (a) AED 4000 = SAR (b) AED 5500 = euro (c) AED 1200 = HKD (d) AED 9000 = JPY

26 176 CHAPTER 3 RATIOS AND PROPORTIONS Practice 4 Use the exchange rate table to change the currencies. (a) Singapore dollar 2000 = AED (b) JPY 5500 = AED (c) KWD 8000 = AED (d) OMR = AED MATHEMATICS FOUNDATION 1

27 WORD PROBLEMS 177 Practice 5 Use the exchange rate table to change the currencies. (a) Noura is going to Germany. She wants to take euro How many AED does she need to buy euro 5000? (b) Badr is going to the UK. He will take AED How many pounds sterling (GBP) will he get for AED 6500? (c) A car costs JPY in Japan. What is the price of the car in AED? (d) Mariam is shopping on the Internet. She orders some items which cost USD 800. What is their cost in AED?

28 178 CHAPTER 3 RATIOS AND PROPORTIONS (e) A barrel of oil costs AED 90. What is the cost of 150 barrels of oil in euros? (f) A computer costs JPY Mohammed wants to buy 25 computers for his company. What is the total cost in AED? (g) Omar is on a business trip to New Zealand. His hotel costs NZD 150 per night. Omar stays for 5 nights. What is the total cost of his hotel stay in AED? (h) Mariam is shopping on the internet. She orders some items which cost USD 800. She gets a 10% discount on her order. What is the cost after discount in AED? MATHEMATICS FOUNDATION 1

29 Allocation According to a Given Ratio 179 Sometimes you want to share or divide some amount or quantity according to a given ratio. For example you may want to: Share some money between two people so that one gets twice as much as the other or Share a hundred computers among three companies so that one company has three times as many computers as the other two companies. Example Salem has Dh 450. He gives his brother Ahmad Dh 250 and his brother Khalid Dh 200. Write a ratio for the money shared between Ahmad and Khalid. Ahmed s share : Khalid s share = 250 : 200 = 5 : 4 Salem has divided Dh 450 between Ahmad and Khalid in the ratio 5 : 4 Example Divide Dh 400 between Fatima and Huda in the ratio 5 : 3 Fatima gets 5 parts and Huda gets 3 parts. The total parts are: = 8 METHOD 1 There are 8 parts altogether and the total to be shared is Dh = 50 (each part is worth Dh 50) 8parts " Dh400 1part " Dh50 Fatima gets 5 parts: 5 Dh 50 = Dh 250 Huda gets 3 parts: 3 Dh 50 = Dh 150 Fatima gets Dh 250 and Huda gets Dh 150. METHOD 2 There are 8 parts altogether and the total to be shared is Dh 400. Fatima gets 8 5 of the money and Huda gets 8 3 of the money. 5 Fatima gets: X 400 = Dh Huda gets: X 400 = Dh Fatima gets Dh 250 and Huda gets Dh 150. Use the method you think is easier to follow.

30 180 CHAPTER 3 RATIOS AND PROPORTIONS EXAMPLE A net income of Dh 72,000 is to be shared among Laila, Nouria and Adel in the ratio 4 : 3 : 2. Find the share of each. Laila s share : Nouria s share : Adel s share = 4 : 3 : 2 Total parts = = 9 Each part is worth 72,000 9 = parts " Dh72, 000 1part " Dh8, 000 Laila s share: 4 Dh 8,000 = Dh 32,000 Nouria s share: 3 Dh 8,000 = Dh 24,000 Adel s share: 2 Dh 8,000 = Dh 16,000 EXAMPLE Faraj, Ahmad and Mohammad are partners in a company. Faraj invests Dh 36,000, Ahmad invests Dh 44,000 and Mohammad invests Dh 16,000. The three partners decide to share First, set up the ratio of their investments: Faraj to Ahmad to Mohammad Dh 36,000 : Dh 44,000 : Dh 16,000 divide by 4000 = 9 : 11 : 4 Total number of shares = = 24 Value per share = 24, = Dh 1000 Faraj gets = Dh 9000 Ahmad gets = Dh 11,000 Mohammad gets = Dh 4000 You can solve this problem without having to simplify the ratio. The original ratio was 36,000 : 44,000 : 16,000 Total = 36, , ,000 = 96, = 0.25 Faraj gets ,000 = Dh 9000 Ahmad gets ,000 = Dh 11,000 Mohammad gets ,000 = Dh 4000 MATHEMATICS FOUNDATION 1

31 Allocation According to a Given Ratio 181 Practice 3 1 Divide Dh 24,000 in the ratio of: (a) 1 : 2 (b) 2 : 3 (c) 10 : 7 : 8 (d) 3 : 3 : 5 : 1 2 Ahmed and Salem plan a trip to Germany during the summer holidays. They agree to share the expenses for the trip in the ratio of 3 : 4 respectively. The trip costs Dh How much should each pay? 3 An inheritance of Dh 224,640 is to be divided among 3 heirs in the ratio 3 : 5 : 7. What is the amount that each of them will receive? among the tenants in the ratio 6 : 8 : 9. The January bill is Dh1840. How much does each tenant pay? much does each receive? shares held. If the three partners have nine shares, two shares and one share respectively, how much does each receive

32 182 CHAPTER 3 RATIOS AND PROPORTIONS Section 3.1 Exercises 1. Find the value of n that makes these fractions equivalent. (a) 4 5 = n 15 (b) 3 = 12 6 n (c) 3 = n (d) n = Find the value of n that makes these ratios equivalent. (a) 8 : n and 4 : 9 (b) 20 : 30 and 2 : n (c) 14 : n and 2 : 3 (d) 4 : 11 and n : 99 MATHEMATICS FOUNDATION 1

33 EXERCISES A car travels at a speed of 160 km/h. How long will it take the car to travel a distance of 450 km? 4. An engine uses 12 L (litres) of fuel every 100 hours. How much fuel is needed to run the engine for 750 hours? 5. On a map the scale is 5 mm : 15 m. A wall is 12 mm long on the map. What is the real length of the wall? 6. The scale of a map is 10 mm : 60 km. The distance between Abu Dhabi and Sharjah is 300 km. What is the distance on the map?

34 184 CHAPTER 3 RATIOS AND PROPORTIONS 7. Use the Currency Exchange Rate table on Page 174 to change the currencies. (a) AED 4000 = euro (b) GBP 3000 = AED (c) AED 5500 = GBP (d) AED 1200 = USD

35 EXERCISES 185 (e) SAR 5500 = AED (f) HKD 4000 = AED (g) AED = USD (h) KWD 3500 = AED

36 186 CHAPTER 3 RATIOS AND PROPORTIONS (i) OMR 5600 = AED (j) AED 900 = JPY 8. Convert AED 500 into Singapore dollars. 9. Mohammed is going to France. He will take AED to spend there. How many euros will Mohammed receive for AED ? MATHEMATICS FOUNDATION 1

37 EXERCISES Omar is going to Hong Kong. He has AED How many Hong Kong dollars (HKD) will he get for AED 2000? 11. Amna is on holiday in the USA. She buys a dress for USD 150. What is the cost of the Dress in dirhams (AED)? 12. John has to send Canadian dollar to Canada. How many dirhams (AED) is this? 13. Ali is on a business trip in the UK. His hotel costs GBP 79 per night. Ali stays for 3 nights. What is the total cost of his hotel stay in dirhams (AED)?

38 188 CHAPTER 3 RATIOS AND PROPORTIONS 14. A box of dates costs AED 48. What is the cost of 50 boxes in US dollars? 15. A barrel of oil costs AED 90. The price increases by 20%. What is the new price of a barrel of oil in US dollers? 16. Hamad and his family are on holiday in Australia. The hotel room costs Australian dollar 120 per night. Hamad stays for 1 week. What is the total cost of the hotel room in dirhams (AED)? 17. A barrel of oil costs AED 90. What is the price of 100 barrels of oil in Canadian dollars? MATHEMATICS FOUNDATION 1

39 EXERCISES Maryam is shopping on the Internet. She buys a book and 3 CDs. The book costs USD 22. The CDs cost USD 35 each. What is the total cost in dirhams (AED)? 19. Hessa is going to India. She has AED How many Indian rupees does she receive? 20 My friend is going to Hong Kong. I give my friend AED150. I ask her to buy 15 metres of silk. The price of the silk is HKD 350. Does my friend have enough money? 21. Aisha is going to New Zealand on holiday. She changes dirhams (AED) to New Zealand dollars (NZD). How many New Zealand dollars (NZD) does she get?

40 190 CHAPTER 3 RATIOS AND PROPORTIONS 22. Mariam is on holidays in Toyko. She buys a digital camera. It costs Japanese yen (JPY). She gets a 10% discount. What is the cost after discount in dirhams (AED)? 23. a) Paul is going to New York. He will take Dh How many US dollars (USD) will he get for his Dh 5400? b) When he returns he still has USD How many dirhams (AED) will he get? 24. Laila orders a dress from Hong Kong. The cost of the dress is Hong Kong dollars (HKD). She gets a discount of 7%. What is the cost of the dress after discount in dirhams (AED)? MATHEMATICS FOUNDATION 1

41 EXERCISES Khaled went to Saudi Arabia to buy camels. The price of a camel was 960 Saudi riyals (SAR). He bought 58 camels. What was the total cost in dirhams (AED)? 26. The cost of a camera in Britain is 650 pounds sterling (GBP). The same camera costs 3000 dirhams (AED) in Dubai. Which camera costs more, and by how much? (Show your work.) 27. Zeyad, Nasser, Eissa and Jalal are the shareholders of a company. Their shares are in much does each one receive? students are allocated to three campuses A, B and C in the ratio 5 : 3 : 8 respectively. How many students are there in each campus?

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