A, B and C can do a piece of work in 9 days, 14 days and 28 days respectively. How long will they taken, if all the three work together?	Choose the correct choice from the following
A) 4.12 days	B) 4.52 days	C) 3.52 days	D) 2.52 days	E) 4.92 days

Rationale: 1 / 9 + 1 / 14 + 1 / 28 = 55 / 252 = > 252 / 55 days = > 4.52 days answer : b
Answer: B