A and B together can complete a certain work in 20 days whereas B and C together can complete it in 24 days. If A is twice as good as C, then in what time will B alone do 40% of the same work?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 12 days.
A and B together can complete a certain work in 20 days.
B and C together can complete the same work in 24 days.
Let total work = LCM of (20 , 24) = 120.
Efficiency of A and B = 120/20 = 6 units...........(1)
Efficiency of B and C = 120/24 = 5 units...........(2)
It is given that the efficiency of A is twice of C, (A = 2C)
From equations 1 and 2 we get,
⇒ 2C + B - B - C = 1 unit
⇒ C = 1 unit.
The efficiency of A = 2 units
The efficiency of B = 6 - 2 = 4 units.
40% of work = 40% of 120 = 48 units.
The number of days taken by B to complete 48 units of work = 48/4 = 12 days.