SOLUTION: Mary is printing flyers for a campus event. She is using two printers to make the copies, the first printer takes twice as long as the second printer to print the same number of fl

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Question 1048767: Mary is printing flyers for a campus event. She is using two printers to make the copies, the first printer takes twice as long as the second printer to print the same number of flyers. If it will take 20 minutes to print the flyers using both printers, how long will it take each of the printers working alone to do the print job?
Answer by josgarithmetic(39838) About Me  (Show Source):
You can put this solution on YOUR website!
SEE THE METHOD FURTHER DOWN THE PAGE FOR A GOOD WAY *

r+2r=1/20 because the sum of the individual rates of the two printers working together is their rate working together. "1" is for "one job of THE flyers", and r is the rate of the slower printer, unknown but can find it.

3r=1%2F20
r=1%2F60

The faster printer would do the job in 60 minutes.
The slower printer would need 120 minutes.

Did that make sense? (SEE THE METHOD BELOW!)




* This method will seem to have less chance for mistakes:
Let x be time for the fast printer to do one job.
This means, 2x is how long for the slow printer to do the same job.
1%2Fx%2B1%2F%282x%29=1%2F20 for one job in 20 minutes for the two printers joined in the task.

2%2F%282x%29%2B1%2F%282x%29=1%2F20
3%2F%282x%29=1%2F20
2x%2F3=20
x=%283%2F2%2920
highlight%28x=30%29

The fast printer would need 30 minutes alone to do 1 job.
The slow printer would need 60 minutes alone to do the same 1 job.