A can do a piece of work in 14 days which B alone can do in 21 days. They begin together but 3 days before the completion of the work, A leaves off. The total number of days for the work to be completed is  Choose the correct choice from the following choices:  A) 6 3/5 days  B) 8 ½ days  C) 10 1/5 days  D) 13 ½ days  E) 7 days
Explanation:   B’s 1 day’s work = 1/21   B’s 3 day’s work = 1/21 ×3 = 1/7   The remaining work finished by both of them = 1 – 1/7 = 6/7   Both together can finish it in 14 × 21/35 days = 42/5 days   Their, 1 day’s work = 5/42   Therefore, the No. of days taken by them together to finish 6/7 work   = 6/7/5/42 = 6/7 × 42/5 = 36/5 = 7 1/5 days   Therefore, the total No. of days for the work to be completed = 3 + 7 1/5 = 10 1/5 days.   Answer: Option 10 1/5 days
<result>C</result>
A can do a piece of work in 14 days which B alone can do in 21 days. They begin together but 3 days before the completion of the work, A leaves off. The total number of days for the work to be completed is