Question 402250
The larger of two printers being used to print the payroll for a major 
corporation requires 40 min to print the payroll.
 After both printers have been operating for 10 min, the larger printer malfunctions. 
The smaller printer requires 50 more min to complete the payroll.
 How long would it take the smaller printer, working alone, to print the payroll?
:
Let s = time (in minutes)required by the smaller printer to do the job
Let the completed job = 1 (payroll printed)
:
Total operating time of the smaller printer is 60 min (10 + 50)
{{{10/40}}} + {{{60/s}}} = 1
:
multiply by 40s, to clear the denominators, results:
10s + 40(60) = 40s
10s + 2400 = 40s
2400 = 40s - 10s
2400 = 30s
s = {{{2400/30}}}
s = 80 minutes, the smaller printer operating alone