A and B can together finish a work in 40days. They worked together for 10days and then B left. After another 18 days, A finished the remaining work. In how many days A alone can finish the job?
Pick one
A) 10
B) 24
C) 60
D) 30
E) 20

Rationale: a + b 10 days work = 10 * 1 / 40 = 1 / 4 remaining work = 1 - 1 / 4 = 3 / 4 3 / 4 work is done by a in 18 days whole work will be done by a in 18 * 4 / 3 = 24 days answer is b
Answer: B