Temple Building

The Answer...

It will take them all two months to complete the temple.

How much of the temple can each of them complete in one month? The Rajastanian will complete one quarter of it, the Suleyman will complete one sixth of it, and the Kaffir will complete one twelfth of it. If all three work together in one month they will complete 1/4 + 1/6 + 1/12 = 1/2, so it will take them all two months to complete the temple.

The Question was...

If a Rajastanian, working alone, can build the temple in four months, a Suleyman can build it in six months, and a Kaffir can build it in twelve months, how long will it take to build the temple if all three of them work together?