A can complete a job in 36 days. Every third day, he is assisted by B who can complete the job alone in 48 days. In how many days will the job be completed?
Show answer & explanation
Correct answer: C
Explanation
A's work in 1 day = 1/36
B's work in 1 day = 1/48
Total work = 144
A's work efficiency = 4
B's work efficiency = 3
Work done in 3 days = 4 + 4 + 4 + 3 = 15
Work done in 27 days (in 9 cycles) = 15 × 9 = 135
A works for the next 2 days = 8
Remaining work = 1
A + B do the remaining work = 1/7
Total time = 27 + 2 + 1/7 = 29 1/7 days