A can do a piece of work in 4 days, while B can do it in 8 days. If they work on alternate days beginning with A, then in how many days will the work be completed?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 5.
A can do a piece of work in 4 days, while B can do it in 8 days
L.C.M(4 and 8) = 8
The efficiency of A = 8/4 = 2 units
The efficiency of B = 8/8 = 1 unit
A will work first, work done = 2 unit
Remaining work = 8 - 2 = 6 units
Now, B will work = 1 unit
Remaining work = 6 - 1 = 5 units
Now, A will work = 2 units
Remaining work = 5 - 2 = 3 units
Now, B will work = 1 unit
Remaining work = 3 - 1 = 2 units
Now, A will work = 2 units, and work will be completed
Total time taken to complete the whole work is 5 days