A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 4 days B had to leave. Then A working with a new worker C complete the remaining work in 3 days . If C works alone , in how many days he can do 40% of the same work ?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 9.
Given :
A and B can complete a work in 15 days and 10 days
A and B work together for 4 days
A and C complete the remaining work in 3 days
Calculations :
A and B one day work = 1/15 + 1/10 = 1/6
A and B work for 4 days = 4 × 1/6 = 2/3
Remaining work = 1 - 2/3 = 1/3
The remaining work is completed in 3 days by A and C
⇒ 1/3 × 1/3 = 1/9
Let C's one-day work be 1/C
⇒ 1/15 + 1/C = 1/9
⇒ 1/C = 2/45
C can complete the whole work in 45/2 days
Time taken by C to complete 40% of the total work
⇒ (40/100) × 45/2 = 9 days
Hence, the Time taken by C to complete 40% of the total work is 9 days.