Problema Solution
At a community savings bank, it takes a computer 28 minutes to process and print checks. When a second computer is used and the two computers work together, the checks can be processed and printed in 20 minutes. How long would it take the second computer by itself to process and print the payroll checks?
Answer provided by our tutors
It takes a computer 28 minutes to process and print checks using the first computer
1/28 checks per min is the rate of the first computer
x = the minutes the second computer needs to process and print the checks alone, x>0
1/x checks per min the rate of the second computer
When a second computer is used and the two computers work together, the checks can be processed and printed in 20 minutes
1/20 checks per min is the together rate
1/28 + 1/x = 1/20
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x = 70 min
x = 1 hr 10 min
The second computer needs 1 hour and 10 min to process and print the payroll checks by itself.