SOLUTION: You estimate that you can do 12 math problems in 45 minutes. How long does it take to do 20?

Question 853432: You estimate that you can do 12 math problems in 45 minutes. How long does it take to do 20?

Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Let x=amount of time needed to do 20 math problems
If you can do 12 math problems in 45 minutes, then you can do 12/45 math problem per min. This means that your work math problems at the rate of 12/45 = 4/15 math problem per min
Soooo (4/15)x=20
x=20(15/4)=75 min
Another, more straightforward, method would be to set up a simple ratio:
12/45 = 20/x
4/15=20/x
4x=300
x=75 min
Hope this helps--ptaylor
RELATED QUESTIONS
You estimate that you can do 12 math problems in 45 min. How long should it take you to... (answered by rfer)

If you can do 12 math problems in 45 minutes. How long should it take you to do 20 math... (answered by ptaylor)

If you can complete 8 math problems in 20 minutes. How long should it take to do thirty... (answered by math_tutor2020,ewatrrr)

If you can do 3 math problems in 4 minutes, how long will it take you to do 27 math... (answered by solver91311)

You can do a job in 12 minutes and your friend takes 15 minutes. How long will it take... (answered by rwm)

Problem: a person can wash their car in 30 minutes. A friend can do it in 20 minutes. (answered by stanbon)

Ivy can do a math problem in 8 minutes, while together Iby and Lyrie can do this problem... (answered by ankor@dixie-net.com)

You must leave for campus in half an hour, or you will be late for your 8:00 Math class.... (answered by Theo)

it takes 20 mintes to do 8 math problems. if he has 28 problems how long will it take him (answered by ptaylor)