A and B together finish a wor in 20 days.They worked together for 15 days and then B left. Afer another 10 days,A finished the remaining work. In how many days A alone can finish the job?  Choose one.
A) 30
B) 40
C) 50
D) 60
E) 70
Explanation:   (A+B)'s 15 days work = (1/20 × 15) = ¾   Remaining work = (1 - ¾) = ¼   Now, ¼ work is done by A in 10 days.   Whole work will bedone by A in (10 × 4 = 40) days.   Answer: 40
<result>B</result>
A and B together finish a wor in 20 days.They worked together for 15 days and then B left. Afer another 10 days,A finished the remaining work. In how many days A alone can finish the job?