A and B can do a piece of work in 30 days, while B and C can do the same work in 24 days and C and A in 20 days. They all work together for 10 days when B and C leave. How many days more will A take t
A). 6 days
B). 12 days
C). 18 days
D). 24 days
18 days
2(A + B + C)'s 1 day's work = ( 1/30 + 1/24 + 120 ) = 15/120 = 1/8 .
Therefore, (A + B + C)'s 1 day's work = 1/2*8 = 1/16 .
Work done by A, B, C in 10 days = 10/16 = 5/8 .
Remaining work = ( 1 - 5/8 ) = 3/8 .
A's 1 day's work = ( 1/16 - 1/24 ) = 1/48 .
Now, 1/48 work is done by A in 1 day.
So, 3/8 work will be done by A in ( 48 x 3/8 ) = 18 days.