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 option
A) 11  B) 28  C) 27  D) 29  E) 271
Explanation:   One day's work of A, B and C = (1/24 + 1/30 + 1/40) = 1/10   C leaves 4 days before completion of the work, which means only A and B work during the last 4 days.   Work done by A and B together in the last 4 days = 4 (1/24 + 1/30) = 3/10   Remaining Work = 7/10, which was done by A,B and C in the initial number of days.   Number of days required for this initial work = 7 days.   Thus, the total numbers of days required = 4 + 7= 
<gadget id="calculator">4 + 7</gadget>
<output>11</output>
11 days.   11nswer: 11) 11 days
<result>A</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?