Working together, printer A and printer B would finish the task in 40 minutes. Printer A alone would finish the task in 60 minutes. How many pages does the task contain if printer B prints 4 pages a minute more than printer A ?  Choose the correct option
A) 250
B) 375
C) 450
D) 480
E) 500
40*A + 40*B = x pages   in 40 mins printer A will print = 40/60 * x pages = 2/3*x pages   thus in 40 mins printer printer B will print x - 2/3*x = 1/3*x pages   Also it is given that printer B prints 4 more pages per min that printer A. In 40 mins printer B will print 160 more pages than printer A   thus 2/3*x - 1/3*x = 160 =&gt; x = 480 pages   Answer: 480
<result>D</result>
Working together, printer A and printer B would finish the task in 40 minutes. Printer A alone would finish the task in 60 minutes. How many pages does the task contain if printer B prints 4 pages a minute more than printer A ?