A, B and C can do a piece of work in 7 days, 14 days and 28 days respectively. How long will they take to finish the work, if all the three work together?
Choose the correct choice from the following options:
A) 4	B) 9	C) 2	D) 11	E) None
1/7 + 1/14 + 1/28 = 7/28 = 1/4   4ll three can finish the work in 4 days   4nswer: 4
<result>A</result>
A, B and C can do a piece of work in 7 days, 14 days and 28 days respectively. How long will they take to finish the work, if all the three work together?