RP7-31 Using Proportions to Solve Percent Problems I

Transcription

1 RP-1 Using Proportions to Solve Percent Problems I These are equivalent statements: 6 of the circles are shaded. of the circles are shaded. 6 is of. 6 : : part whole 1. Write four equivalent statements for the picture. b) are shaded 6 are shaded is of 6 : 6 : c) d). Write a pair of equivalent ratios for the picture. b) c) is 1 of 8 6 is of 8 is 1 of : 8 1 : : : : : part whole part whole part whole. For the statement, write a pair of equivalent ratios equivalent fractions. 1 is of 1 : : part b) 1 is of 16 : : part COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION 6 Ratios Proportional Relationships -1

2 . Write a question mark where you are missing a piece of information. 1 is of what number? 1 :? : part 1? b) 6 is how many quarters of 8? 6 : 8? : part 6? 8 c) What is of 1? : : part d) is how many fifths of? : : part. Write a pair of equivalent ratios a pair of equivalent fractions. 1 is what percent of 0? 1 : 0? : part 1? 0 b) What is 0% of 0? : part : c) 1 is what percent of 8? : part : d) 6 is % of what number? : part : 6. Write the two pieces of information you are given what you need to find (?). Then write an equation for the problem. What percent of 0 is? part whole 0 percent?? 0 b) If 11 is 0%, what is %? part whole? percent? c) What is 6% of? part? whole percent? COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION d) If is 16%, what is %? part whole percent What percent of 0 is? part whole percent f) What is % of 18? part whole percent g) is what percent of? part whole percent Ratios Proportional Relationships -1

3 If subway tickets cost $, how much do 0 tickets cost? Write the ratio of dollars to tickets as a fraction, then find an equivalent fraction by multiplying: Step 1: Step : Step : Dollars? Tickets , so 0 tickets cost $ Solve the proportion. Draw arrows show what number you multiply by. 0 b) 1 1 c) d) 8 f) 18 g) 1 0 h) 8. Solve the proportion the way you did in Question. Hint: The arrow will point from right to left. 1 b) 1 1 c) 1 d) 18. Complete the equivalent fraction. Start by reducing the given fraction. The first one has been started for you. 8 1 b) 6 1 c) 0 d) f) 0 6. Tanya is paid $ for hours of work. How much would she be paid for 6 hours of work? 11. Three centimeters on a map represent km in real life. If a lake is cm long on the map, what is its actual length? 1. A goalie stopped 1 out of every 1 shots. There were shots. How many goals were scored? The Great Ocean Deep Heights Lake Mountain Emerald Forest COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION 8 Ratios Proportional Relationships -1

4 RP- Using Proportions to Solve Percent Problems II 1. Write a proportion to represent the percent problem. Solve the proportion. What percent of 0 is? part whole percent b) If 6 is %, what is %? part whole percent c) What is 1% of? part whole percent d) What is 1% of 0? part whole percent is what percent of? f) 6 is % of what number? g) is 80% of what number?. Explain why the proportion x will be easy to solve.. Write a proportion a b x to represent the problem. Solve by first writing a b in lowest terms. What percent of 1 is? b) What percent of is 6? c) What percent of 0 is 1?. Write a proportion to represent the percent problem. Find an equivalent ratio to rewrite the proportion. Solve the new proportion. If 6 is 0%, what is %? part 6 whole x percent x Hint: Start by writing 0% as an equivalent ratio with numerator. 0 b) What is % of 8? Hint: Start by writing % as an equivalent ratio with denominator. part whole percent COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION c) What percent of 60 is? part whole percent d) What is 60% of 1? part whole percent. Solve. is 60% of what number? b) What is % of? c) 16 is 80% of what number? d) What percent of 60 is? Ratios Proportional Relationships -

5 6. If % of students use an MP player, how many students use an MP player?. Ten students in a class (0% of the class) bike to school. How many students are in the class? REMINDER: of a number is. What is the number? part? whole 0 0? The number is. 8. What is the number? of a number is b) of a number is c) of a number is 11. A box holds red blue beads. Find the total number of beads in the box. of the beads are red. Six beads are red. b) of the beads are blue. Twelve beads are blue. c) 60% of the beads are red. Fifteen beads d) The ratio of red beads to blue beads is :. are red. There are 0 red beads. Hint: What fraction of the beads are red?. Emma Sun share a sum of money. Emma receives of the money. Sun receives $. What fraction of the sum did Sun receive? b) How much money did Emma Sun share? 11. At Franklin Middle School, 8 of the students take a bus to school, walk, the rest bike. There are 0 students who bike to school. How many students are in the school? 1. In a fish tank, of the fish are red, 1 are yellow, the rest are green. There are more red fish than green fish. What fraction of the fish are green? b) What fraction of the total number of fish does represent? Hint: is the difference c) How many fish are in the tank? between the number of red green fish. 1. In Carl s stamp collection, 0% of the stamps are American the rest are international. Carl has 00 more American stamps than international stamps. How many stamps does he have? 1. On an LED sign, 1 of the lights are yellow the rest are blue red. There are twice as many blue lights as yellow lights, there are 00 red lights on the sign. How many LED lights of all colors are on the sign? COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION 0 Ratios Proportional Relationships -

6 RP- Solving Equations (Introduction) 1. Each bag contains the same number of apples. Let x be the number of apples in one bag. Write an expression for the total number of apples. b) c). Write the total number of apples two ways to make an equation. There are apples in total. b) There are 11 apples in total. c) There are 0 apples in total.. The scales are balanced. Write an equation to show this. b) Remove the same number of apples from each side to keep the scales balanced. Leave the bag by itself on one side. Write the new equation. c) How many apples are in the bag? COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION Finding the value of a variable in an equation is called solving for the variable. To solve x +, subtract from both sides of the equation so that one side has only x.. Subtract from both sides of the equation. x x b) + x - - c) + x - -. Subtract the same number from both sides of the equation so that x is by itself. x b) + x c) x x x 6 d) 0 x d) + x - - Ratios Proportional Relationships - 1

7 6. Solve the equation by subtracting the same number from both sides. x b) + x 1 c) 6 x + 8 d) x + 1. The scales are balanced. Write an equation to show this. b) Divide the quantities on both sides into the same number of equal groups. Leave one group on each side. Write an equation. c) How many apples are in each bag? 8. Divide both sides of the equation by the same number so that x is by itself. x 1 b) 8x 8 8 c) 1 6x 6 6 d) x. Solve the equation by dividing both sides of the equation by the same number. x 0 b) x 18 c) x d) x 6 x 0 x 6 x 1,000 f) x 680 g) 8x 18 h) x 1. Solve the equation by doing the same thing to both sides of the equation. x + 1 b) x 1 c) + x d) x + x 11 f) 1x g) x + 1 h) x COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION Ratios Proportional Relationships -

8 REMINDER: You can subtract a negative number by adding its opposite. Example: ( ) + 11 You can add a negative number by subtracting its opposite. Example: + ( ) 11. Solve the equation by subtracting the same number from both sides. x + ( ) b) x + ( 8) 1 c) x + 1 d) x + 1 x ( ) x + x 1 x + 8 f) x + ( ) 8 g) x + 8 h) x + ( ) 8 REMINDER: You can multiply divide positive negative numbers by multiplying their absolute values using the rules for signs: (+) (+) + (+) ( ) ( ) (+) ( ) ( ) + (+) (+) + (+) ( ) ( ) (+) ( ) ( ) + 1. Solve the equation by dividing both sides of the equation by the same number. x 1 b) x 1 c) x ( ) 1 d) x 1 COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION x ( 6) f) 1x g) 1 x h) 1 x 6 Ratios Proportional Relationships -

9 RP- Cross-Multiplication (Introduction) 0. means the same thing as 0., so Change the equation to a division statement, then to a multiplication statement. 8 b) c) 11 d) 1. Change the equation to a multiplication statement. 1. b) 1. c). 6 1 d) x f). g) 1 1. h) 1 t You can turn equivalent fractions into equivalent products. Multiply both fractions by the product of their denominators. Example:. Multiply both fractions by 1, the product of their denominators Rewriting as 1 is called cross-multiplying because 1 the products are obtained by multiplying the numbers in an shape: 1. Check that cross-multiplying works for the equivalent fractions b) c) d) f) g) h) COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION Ratios Proportional Relationships -

10 . Cross-multiply write (equal) or (not equal) in the box. Are the fractions equivalent? 1 b) 1 Are 1 equivalent? Are equivalent? c) 81 d) 8 Are 81 equivalent? Are 8 equivalent? 1 0 f) 6 g) 1 h) You can cross-multiply if you have equivalent complex fractions, too. Example:, so are equivalent.. Are the complex fractions equivalent? Cross-multiply to check. b) c) Bonus d) Bonus 1 COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION 6. Complete the equivalent fraction. Start by reducing the given fraction. i) 8 ii) 1 iii) 6 1 b) Use cross multiplication to solve the problems in part. c) How would you solve the problem: mentally (by reducing the fraction) or with cross multiplication? Find the missing number. i) 0 18 ii) iii) 0 0 Ratios Proportional Relationships -

11 RP- Using Equations to Solve Proportions You can solve a proportion by cross-multiplying solving an equation. 6 x 6 6 x 6 x 6 6 x 6 x 6 x 1. Cross-multiply to write an equation for x. (Do not solve.) x b) x c) x x 11 x d) x f) 1 x x g) x h) 1 x. Solve for x. x b) 6 x c) 6 d) x x x f) 1 x 6 g) 8 x Bonus x You can solve percent problems by writing a proportion then cross-multiplying. x 0 Example: What is 0% of? so x 0 x 60 x 60 x 6.. Solve by first writing a proportion. What is 0% of 6? b) is % of what number? c) is what percent of 1? Bonus is what percent of 8? COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION 6 Ratios Proportional Relationships -

12 Answer all problems in your notebook. Write an equation for each problem solve the equation. Use a calculator when you need it.. What percent of is 8? b) What percent of 1 is? c) What percent of 18 is? d) What percent of 1 is 0.6?. Round the solution to the nearest one. is about what percent of? b) About what percent of 1 is? c) is about what percent of? d) About what percent of,60 is,000? 1. is about what percent of? 6. If Grace has read of the pages in her library book, about what percent of the book has she read so far?. Find the amount. Include units in your answers. 6% of g b) 11% of 0 m c) % of 11 ml d) % of 8 m 0% of, min 8. About % of students are vegans. About how many students are vegans?. A basketball team won 60% of the games it played this year. What percent of the games played did the team lose? b) How many games did the team lose?. What is % if % is 0? b) 1% is 0? c) % is 1? COPYRIGHT 01 JUMP MATH: NOT TO BE COPIED. CC EDITION 11. About what is %? Round the solution to the nearest one. is % b) is % c) is % 1. In a Grade class, 6 of the students, or about %, were on the honor roll. How many students are in the class? Bonus Ben bought a new computer at a 1% discount. He paid $1,00. What percent of the original price did he pay? b) What was the original price? c) How much money did Ben save by buying the computer at a discount? Ratios Proportional Relationships -