A, B and C can do a piece of work in 24, 30 and 40 days respectively. They start the work together but C leaves 4 days before the completion of the work. In how many days is the work done? Choose one:	A) 11	B) 5	C) 70	D) 11	E) 13

Rationale: x / 24 + x / 30 + x / 40 = 1 x = 11 days answer : d
Answer: D