Solve proportions: word problems
Learn with an example
✈️ Olivia bought 16 postcards during 4 days of holiday. After 5 days of holiday, how many total postcards will Olivia have bought? Assume the relationship is directly proportional.
______postcards
- Set up a proportion and solve for n.
- 16 postcards / 4 days = n postcards / 5 days
- 16/4 ( 4.5 ) = n/5 ( 4.5 ) ——-> Multiply both sides by 4 · 5
- 16 · 5 = 4n ——> Simplify
- 80 = 4n —–> Multiply
- 20 = n ——> Divide both sides by 4
- After 5 days of holiday, Olivia will have bought a total of 20 postcards.
✈️ Baldwin read a total of 10 books over 5 months. After belonging to the book club for 9 months, how many books will Baldwin have read in all? Assume the relationship is directly proportional.
______ books
- Set up a proportion and solve for n.
- 10 books / 5 months = n books / 9 months
- 10/5 ( 5.9 ) = n/9 (5.9) ——>Multiply both sides by 5 · 9
- 10 · 9 = 5n ——–> Simplify
- 90 = 5n ——> Multiply
- 18 = n ———> Divide both sides by 5
- After belonging to the book club for 9 months, Baldwin will have read 18 books in all.
✈️ Chad took a total of 6 quizzes over the course of 2 weeks. How many weeks of school will Chad have to attend this quarter before he will have taken a total of 9 quizzes? Assume the relationship is directly proportional.
_____ weeks
- Set up a proportion and solve for n.
- 6 quizzes / 2 weeks = 9 quizzes / n weeks
- 6/2 ( 2n ) = 9/n (2n) ——-> Multiply both sides by 2n
- 6n = 9 · 2 ——> Simplify
- 6n = 18 ——–> Multiply
- n = 3 ——-> Divide both sides by 6
- Chad will have to attend 3 weeks of school this quarter before he will have taken a total of 9 quizzes.
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