Working together, it takes two computers
10 minutes to send out a company's email. If it takes the slower computer
35 minutes to do the job on its own, how long will it take the faster computer to do the job on its own?
Do not do any rounding.

Question

Working together, it takes two computers 
10 minutes to send out a company's email. If it takes the slower computer 
35 minutes to do the job on its own, how long will it take the faster computer to do the job on its own?
Do not do any rounding.

Champion · Answer

use the idea

rate * time = 1 job
and we need the rate = jobs per minute
in this problem, one of the computers does one job in 35 minutes
that means its rate is 1/35

call the other rate x  (for unknown)

then together (we add their rates) we can say
(1/35 + x) * 10 = 1

can you solve for x?