A can complete a task in 16 days, and B can complete the same task in 24 days. If A and B work on alternate days starting with A, in how many days will the task be completed?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 19
Work done by A in 1 day = 1/16
Work done by B in 1 day = 1/24
Work done in 2 days (A + B) = 1/16 + 1/24 = 5/48
Remaining work after 2 days = 1 – 5/48 = 43/48
Work done in 18 days (9 cycles) = 9 × 5/48 = 45/48
Remaining work = 1 – 45/48 = 3/48 = 1/16
On 19th day, A works and completes 1/16 → task finished