A can complete 2/5th of the work in 12 days, and B can complete 7/8th of the same work in 21 days. Find the number of days in which A and B together can complete the work.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 40/3 days
Given that
A can complete 2/5th of the work in 12 days
A can complete the whole work in 12 × (5/2) = 30 days
B can complete 7/8th of the same work in 21 days
B can complete the whole work in 21 × (8/7) = 24 days
Total work = LCM (30, 24) = 120 days
The efficiency of A = 120/30 = 4
The efficiency of B = 120/24 = 5
Hence, A and B together can complete the work in 120/(4 + 5) = 120/9 = 40/3 days