A can complete a certain work in 35 days and B can complete the same work in 15 days,. They worked together for 7 days, Then B left the work , in how many days will A alone complete 60% of the remaining work ?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 7.
A can complete a certain work = 35 days and,
B can complete the same work = 15 days
L.C.M(35 and 15)= 105 units
The efficiency of A = 105/35 = 3 units
The efficiency of B = 105/15 = 7 units
They worked together for 7 days, Then B left the work
Work done in 7 days = 7 × (3 + 7) = 7 × 10 = 70 units
Remaining work = 105 - 70 = 35 units
⇒ 60% of 35 = 21 units
Time taken by A = 21/3 = 7 days