proportion | MathCelebrity Forum

# proportion

1. ### A half is a third of it. What is it?

A half is a third of it. What is it? Let "it" be an arbitrary variable, let's call it x. A third of 'it' means we divide x/3 The word is means equals, so we have: x/3 = 1/2 Using our proportion calculator, we get: x = 1.5 or 3/2 or 1 & 1/2
2. ### How long does it take to cook 20 eggs if it takes 10 minutes to cook 4 eggs

How long does it take to cook 20 eggs if it takes 10 minutes to cook 4 eggs Set up a proportion of minutes to eggs where m is the number of minutes it takes for 20 eggs. 10 minutes / 4 eggs = m/20 Solving for m, we get: m = 50
3. ### If gum were 3 packs for \$1.00, how many packs would you get for \$7.00

If gum were 3 packs for \$1.00, how many packs would you get for \$7.00 3 packs / \$1.00 * \$7.00 = 21 packs
4. ### George and William both ran a one mile race. William won the race with a time of 4 minutes and 30 se

George and William both ran a one mile race. William won the race with a time of 4 minutes and 30 seconds. If George was 480 feet behind William when the race finished, how long did it take George to run the entire mile? (George continued to run at the same pace.) When the race was done, George...
5. ### It took 3.5 gallons of paint to cover a wall that is 985 square feet. How many gallons will it take

It took 3.5 gallons of paint to cover a wall that is 985 square feet. How many gallons will it take to cover a wall that is 6501 square feet? Set up a proportion of gallons of paint to square feet where n is the number of gallons of paint to cover 6501 square feet 3.5/985 = n/6501 Using our...
6. ### A 3-foot stick casts a shadow of 8 feet. If at the same time a tree casts a shadow of 15 feet, how t

A 3-foot stick casts a shadow of 8 feet. If at the same time a tree casts a shadow of 15 feet, how tall is the tree? Set up a proportion of height to shadow length where t is the height of a tree: 3/8 = t/15 Using our proportion calculator, we get: t = 5.625
7. ### If a speedometer indicates that a car is traveling at 65 kilometers per hour, how fast is the car tr

If a speedometer indicates that a car is traveling at 65 kilometers per hour, how fast is the car traveling in miles per hour? (Round to the nearest tenth.) Set up a proportion of miles per kilometers: 0.621/1 = n/65 Using our proportion calculator, we get: n = 40.365
8. ### A typical human adult weighs 150 pounds, while a human newborn weighs approximately 7 pounds. An adu

A typical human adult weighs 150 pounds, while a human newborn weighs approximately 7 pounds. An adult female Western Grey Kangaroo weighs about 30 kilograms and gives birth to babies who are approximately one gram. If human babies were proportionally the same weight as adults as Western Grey...
9. ### Rick sold a total of 75 books during the first 22 days of May. If he continues to sell books at the

Rick sold a total of 75 books during the first 22 days of May. If he continues to sell books at the same rate, how many books will he sell during the month of May? Set up a proportion of days to books where n is the number of books sold in May: 22/31 = 75/n Using our proportion calculator and...
10. ### A yardstick casts a shadow of 8 inches. At the same time, a tree casts a shadow of 52 feet. How tall

A yardstick casts a shadow of 8 inches. At the same time, a tree casts a shadow of 52 feet. How tall is the tree? Setup a proportion of height to shadow distance where h is the height of the tree: 36/8 = h/52 Using our proportion calculator, we get: h = 234 feet
11. ### A goal for many elite runners is to complete a mile in 4 minutes. At what speed (in miles per hour)

A goal for many elite runners is to complete a mile in 4 minutes. At what speed (in miles per hour) is a runner traveling when he completes a mile in 4 minutes? 4 minutes/60 minutes per hour = 1 mile / n miles 4/60 = 1/15, so n = 15 miles per hour
12. ### A giant tortoise can live 175 years in captivity. The gastrotrich, which is a small aquatic animal,

A giant tortoise can live 175 years in captivity. The gastrotrich, which is a small aquatic animal, has a life-span of only 3 days (72 hours). If a gastrotrich died after 36 hours, a giant tortoise that lived 87.5 yeas would live proportionally the same because they both would have died halfway...
13. ### If 3.75 inches on a map are equal to 18.75 miles, how many miles are 5 inches equal to?

If 3.75 inches on a map are equal to 18.75 miles, how many miles are 5 inches equal to? Set up a proportion of inches to miles where m is the number of miles for 5 inches: 3.75/18.75 = 5/m Using our proportion calculator, we get: m = 25 miles
14. ### A flea is very small, but can jump very high. For example, a flea that is 1/8 inch tall can jump 12

A flea is very small, but can jump very high. For example, a flea that is 1/8 inch tall can jump 12 inches in height. If a child who is 4 feet tall had the ability to jump like a flea, how high could she jump? Set up a proportion of height to jump height where j is the jump height of the child...
15. ### A recipe that makes 25 oatmeal cookies calls for 2.5 cups of oats and one cup of sugar. Jerry needs

A recipe that makes 25 oatmeal cookies calls for 2.5 cups of oats and one cup of sugar. Jerry needs to make 195 cookies for his school party. How many cups of oats will he need? Set up a proportion of oats to cookies where c is the number of cups needed to make 195 cookies 2.5/25 = c/195 Using...
16. ### A 1.5 inch tall preying mantis will sometimes hold its ground and attempt to fight a person who is 6

A 1.5 inch tall preying mantis will sometimes hold its ground and attempt to fight a person who is 6 feet tall. If a person who is 6 feet tall is engaged in a battle with an animal that was proportionally as tall as the person is to the preying mantis, how tall would the animal be? In terms of...
17. ### A person who had \$1,000,000 gave \$100 to charity. How much must a student who has \$100 give to chari

A person who had \$1,000,000 gave \$100 to charity. How much must a student who has \$100 give to charity to give proportionally the same as the millionaire? Set up a proportion of wealth owned to donation where x is the amount the student gives: 1000000/100 = 100/x Using our proportion...
18. ### A stick that is ten feet tall casts a shadow of 12 feet. If a tree has a 96 foot shadow, how tall is

A stick that is ten feet tall casts a shadow of 12 feet. If a tree has a 96 foot shadow, how tall is the tree? Set up a proportion of wood height to shadow length where h is the height of the tree: 10/12 = h/96 Using our proportion calculator, we get: h = 80 feet
19. ### If there are 9000 seconds in 2.5 hours, how many hours are there in 13,500 seconds?

If there are 9000 seconds in 2.5 hours, how many hours are there in 13,500 seconds? Setup a proportion of hours to seconds where h is the number of hours in 13,500 seconds 2.5/9000 = h/13500 Using our proportion calculator we get: h = 3.75 hours
20. ### Erica is 5 feet tall and has a shadow of 2 feet. A nearby tree has a shadow of 18 feet. How tall is

Erica is 5 feet tall and has a shadow of 2 feet. A nearby tree has a shadow of 18 feet. How tall is the tree? Set up a proportion of feet tall to shadow height where n is the height of the tree 5/2 = n/18 Using our proportion calculator, we get: n =45 feet