SOLUTION: A two year- old computer can be perform a certain job in 3hours if a new computer is allowed to assist the older computer, the job can be done in 1hour 20minutes how long would it

Question 629005: A two year- old computer can be perform a certain job in 3hours if a new computer is allowed to assist the older computer, the job can be done in 1hour 20minutes how long would it take the new computer to perform the job on its own?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A two year- old computer can be perform a certain job in 3hours if a new computer is allowed to assist the older computer, the job can be done in 1hour 20minutes how long would it take the new computer to perform the job on its own?
----
old comp. rate: 1/3 job/hr
together rate: 1/(7/6) = 6/7 job/hr
new comp. rate: 1/x job/hr
-----
Equation:
rate + rate = together rate
1/3 + 1/x = 6/7
Multiply thru by 21x to get:
6x + 21 = 18x
12x = 21
x = 7/4 hr = 1 hr 45 minutes (time for the new computer to do the job)
==================
Cheers,
Stan H.
RELATED QUESTIONS
An old computer can do the weekly payroll in 5 hours. A newer computer can do the same... (answered by Theo)

A new computer can complete a complex biochemistry calculation in 7 hours less than an... (answered by jorel1380)

A computer can process the payroll for Hometel in 13 hours. An older back-up computer... (answered by josgarithmetic)

A computer password is to be made up consisting of four alphabetical characters. How many (answered by Fombitz,Alan3354)

solve. Round to the nearest tenth of necessary A certain computer can grade 2000... (answered by Theo,robertb)

An old computer takes 15 minutes longer to print a document than the new computer.... (answered by josgarithmetic,advanced_Learner)

The computer at the bank can process bank statements in 15 hours. A new faster computer... (answered by Fombitz)

It takes a computer 8 days to print all of the letters for a sweepstakes. A new computer... (answered by checkley77)

Two computers A and B are to be marketed. A salesman who is assigned the job of finding... (answered by ikleyn)