Working alone, Printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 30, and 40 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?	Choose the correct option.
A) 4/11
B) 1/2
C) 15/22
D) 120/7
E) 11/4
P1 takes 12 hrs   Rate for P2P3 together = 1/30 + 1/40 = 7/120   Therefore they take 120/7   Ratio = 120/7 = 120/7
<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, 30, and 40 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?