A and b working alone can complete a work in 8 days and 12 days, respectively. They started working together, but A left 2 days before completion of the work. In how many days was the work completed?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 6
Given:
A and b working alone can complete a work in 8 days and 12 days.
They started working together, but A left 2 days before completion of the work.
Formula used:
Efficiency = Work/Day ------ (1)
Calculations:
Total work = LCM of 8 and 12 = 24 units
Using equation (1)
Efficiency of A = 24/8 = 3 units
Efficiency of B = 24/12 = 2 units
Last two days of work done by B = 2 × 2 = 4 units
Work done by A and B = 3 + 2 = 5 units
Days to complete the remaining work = 20/5 = 4 days
Total required days = 4 + 2 = 6 days