A, B and C can do a piece of work in 15, 20 and 30 days. They undertake to complete the work for Rs.

A, B and C can do a piece of work in 15, 20 and 30 days. They undertake to complete the work for Rs. 810. How much share of A exceeds that of B ?

A. Rs. 90

B. Rs. 180

C. Rs. 270

D. Rs. 360

E. None of the above

Answer: A. Rs. 90

A's 1 day's work = $1/50$
B's 1 day's work = $1/20$
C's 1 days's work = $1/30$
Ratio of their shares = $ 1/15:1/20:1/30$ = 4 : 3 : 2
Thus, A's share in Rs. 810
=Rs. $4/9$ x 810 = Rs. 360
and, B's share in Rs. 810.
=Rs. $3/9$ x 810 = Rs. 270
Hence, difference between their shares = Rs. (360 - 270) = Rs. 90.

Posted in: Time & Work - Aptitude - Mathematics