George does 3/5th of a piece of work in 9 days. He then calls in Paul , and they finish the work in 4 days. How long would Paul take to do the work by himself?
Choose the correct choice from the following choices:
A) 30	B) 40	C) 50	D) 60	E) 70

Rationale: 100 % work will be done by george in 15 days ( 1 / 15 ) 9 + ( 1 / 15 + 1 / x ) 4 = 1 solving this eqn . we get x = 30 hence paul take to do the work in 30 days answer : a
Answer: A