Question

A and B can do a work in 8 days, B and C in 12 days and A and C in 16 days. In what time could

they do it, all working together?​

Answer 1

A and B do (1/8)th of the work in a day.

B and C do (1/12)th of the work in a day.

A and C do (1/16)th of the work in a day.

2A, 2B and 2C do (1/8)+(1/12)+(1/16) = (18/144)+(12/144)+(9/144) = (39/144) or (13/48)th of the work in a day.

Or A, B and C do (13/96)th of the work in a day.

So A, B and C together will complete the whole work in 96/13 or 7 and 5/13th of the 8th day.