Question

A and B working separately can do a piece of work in 10 days and 15 days respectively. If they work on alternate days beginning with A, in how many days will the work be completed ?

• A. 12
• B. 10
• C. 9
• D. 6

Answer 1

Answer:

A. 12

total work = LCM(10,15) = 30 work done by A in one day = 1/10 work done by A in one day = 1/15 work done by A + B in 2 days = 1/10 + 1/15 = 1/6 work done by A + B in one day = 1/12 Time taken by A and B to complete the work = 12 days