SOLUTION: If it takes 8 students 20 minutes to wash 3 cars, how many cars can 16 students wash in 30 minutes

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Question 755550: If it takes 8 students 20 minutes to wash 3 cars, how many cars can 16 students wash in 30 minutes
Answer by josgarithmetic(39627) About Me  (Show Source):
You can put this solution on YOUR website!
More than half the solution process is here:
8 students 20 minutes to wash 3 cars
By intuition for the ratio, 8 students need 20/3 minutes to wash 1 car.
The job seems to be, "wash one car", and we want the rate for 1 student.
One student will need 8 times longer to wash 1 car, so:
1 student needs 8%2A20%2F3 minutes to do the job of washing 1 car.

This one-student job rate is then 1%2F%28%288%2A20%29%2F3%29=highlight%283%2F%28240%29%29 jobs per minute.

Can you do the rest of the solution? {when the student work at the same time, their rates, each the same, are additive.}