Bunuel wrote:
A is twice as efficient as B and B is thrice as efficient as C. If all three together can complete a work in 10 days, find the difference in the number of days taken to complete the work when A and B work together and when B and C work together.
A. 25
B. 125/6
C. 125/7
D. 125/8
E.125/9
Set A, B, C as rates. Then A = 2B = 6C. The combined rate of A + B + C = 6C +3C + C = 10C = 1/10 (it takes 10 days to complete the job, so each day they complete 1/10).
Then C = 1/100, B = 3/100, A = 6/100.
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