A can do a piece of work in 8 days and B in 24 days. They begin together, but 4 days before the completion of the work, A leaves. Find the number of days taken by A and B to complete the entire work.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 9 days
The number taken to complete the work = y(x + z)/(x + y)
[Where x and y are the number of days taken by A and B and z is the number of days before A left]
x = 8, y = 24 and z = 4
Days required = 24(8 + 4)/(8 + 24) = 24(12)/32 = 9 days