Working alone, Printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 25, and 30 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? Answers.
A) 4/11  B) 1/2  C) 15/22  D) 150/11  E) 11/4
P1 takes 12 hrs   Rate for P2P3 together = 1/25 + 1/30 = 11/150   Therefore they take 150/11   Ratio = 150/11 = 150/11
<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, 25, and 30 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?