A, B and C can do a piece of work in 24, 30 and 40 days respectively. They start the work together but C leaves 4 days before the completion of the work. In how many days is the work done?
Choose the correct answer
A) 14 days	B) 21 days	C) 22 days	D) 11 days	E) 43 days
11 days   11 days   x/24 + x/30 + x/40 = 1   x = 11 days
<result>D</result>
A, B and C can do a piece of work in 24, 30 and 40 days respectively. They start the work together but C leaves 4 days before the completion of the work. In how many days is the work done?