Question

A and b working separately can do a piece of work in 9 and 12 days respectively.if they work a day alternatively.a beginning,in how many days the work will be completed?

Answer 1

A can finish 1/9 of the work in 1 day

B can finish 1/12 of the work in 1 day

In 2 days (A work for 1 day then B work for the next day) = 1/9 + 1/12 = 7/36 of the work is completed.

Number of 2 days needed = 36/7 = 5 1/7 days

Number of days needed = 5 1/7 x 2 = 10 2/7 = 11 days

Number of whole days needed to complete the project = 11 days