Working alone, Printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 16, and 18 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 choice from the following options:
A) 4/11
B) 1/2
C) 15/22
D) 144/17
E) 11/4
P1 takes 12 hrs   Rate for P2P3 together = 1/16 + 1/18 = 17/144   Therefore they take 144/17   Ratio = 144/17 = 144/17
<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, 16, and 18 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?