A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
Choose the correct choice from the following choices.
A) 15 days
B) 12 days
C) 13 days
D) 20 days
E) 25 days
15 days'S 2nd day work = (1/20 * 2) = 1/10   (15 days+B+C)'S 1 day's work = (1/20 + 1/30 + 1/60) = 1/10   work done in 3 days = 1/5   =&gt; whole work will be done in (3*5)= 
<gadget id="calculator">(3*5)</gadget>
<output>15</output>
15 days   15 daysNSWER 15 days
<result>A</result>
A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?