Question

A,B,C complete a given work in 12, 42 and 28 days respectively. If all three
of them work together, in how many days the work will get completed ?
41 days
24 days
11 days
O 7 days

Answer 1

Step-by-step explanation:

A, B and C do their work (Work done/day).

A works 1/12,

B works 1/42

and C works 1/28.

When they work together,

1/12 + 1/42 + 1/28 = 1/2* (1/6 + 1/21 + 1/14) = 1/2* (1/3 * (1/2 + 1/7) + 1/14) =

1/2 * ((1/3 * 9/14) + 1/14) = 1/2 * 1/14 * (4) = 1/7

Since their rate of doing work is 1/7, the number of days they would take is 7.