A alone can do a work in 20 days, B alone in 30 days. They work together for 6 days, then A leaves. How many more days will B take to finish the remaining work?
Show answer & explanation
Correct answer: C
Explanation
Given:
A completes the work in = 20 days
B completes the work in = 30 days
Both work together for = 6 days
According to the formula:
Work done in 1 day = 1 / Total days
A's work in 1 day = 1/20
B's work in 1 day = 1/30
(A + B)'s work in 1 day
= 1/20 + 1/30
LCM = 60
= 3/60 + 2/60
= 5/60
= 1/12
Work done in 6 days = 6 × 1/12 = 1/2
Remaining work = 1 − 1/2 = 1/2
Now, B will work alone
B's work in 1 day = 1/30
Time required = (1/2) ÷ (1/30) = 15 days