A, B and C can do a piece of work in 24 days, 30 days and 40 days respectively. They began the work together but C left 4 days before the completion of the work. In how many days was the work completed?  Choose the correct choice: A) 12 days B) 16 days C) 18 days D) 11 days E) 38 days
One day work of A, B and C = 1/24 + 1/30 + 1/40 = 1/10 Work done by A and B together in the last 4 days = 4*(1/24 + 1/30) = 3/10   Remaining work = 7/10   The number of days required for this initial work = 7 days.   The total number of days required = 4 + 7= 
<gadget id="calculator">4 + 7</gadget>
<output>11</output>
11 days.Answer: 11 days
<result>D</result>
A, B and C can do a piece of work in 24 days, 30 days and 40 days respectively. They began the work together but C left 4 days before the completion of the work. In how many days was the work completed?