A and B can complete a piece of work in 12 days and 18 days, respectively. A begins to do the work and they work alternately, one at a time, for one day each. The whole work will be completed in ________.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. .
A can finish the work in 12 days
B can finish the work in 18 days
LCM of 12 and 18 = 36
Efficiency of A = 36/12 = 3 unit per day, B = 36/18 = 2 unit per day
Their 2 days work = 3 + 2 = 5 unit
7 × 2 days = 5 × 7
14 days = 35 unit
Remaining work done by A = (36 - 35)/3 = 1/3 days
total time = 14 + 1/3 = days