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?
Select the correct option:	A) 4.12 days	B) 4.52 days	C) 3.52 days	D) 2.52 days	E) 4.92 days
1/9 + 1/14 + 1/28 = 55/252   =&gt; 252/55 days   =&gt;4.52 days   ANSWER:4.52 days
<result>B</result>
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?