Working alone, Printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 40, and 50 hours, respectively. What is the ratio of the time it takes Printer X to do the job, working alone at its rate, to the time it takes Printers Y and Z to do the job, working together at their individual rates? Select the correct option.
A) 4/11 B) 1/2 C) 15/22 D) 200/9 E) 11/4
P1 takes 12 hrs   Rate for P2P3 together = 1/40 + 1/50 = 9/200   Therefore they take 200/9   Ratio = 200/9 = 200/9
<result>D</result>
Working alone, Printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 40, and 50 hours, respectively. What is the ratio of the time it takes Printer X to do the job, working alone at its rate, to the time it takes Printers Y and Z to do the job, working together at their individual rates?