Choose the most appropriate option.
A can do a piece of work in 8 days and B alone can do the same work in 10 days. A and B agreed to do the work together for Rs. 720. With the help of C, they finished the work in 4 days. How much C is to be paid?
C's 1-day work`=1/4-(1/8+1/10)`
A's wages: B's wages: C's wages`=1/8: 1/10 : 1/40=5:4:1`
∴ C's share (for 4 days)`=720/10xx1=72`
= Rs. 72