A can finish a piece of work in 5 days. B can do it in 15 days. They work together for two days and then A goes away. In how many days will B finish the work?  Choose the most appropriate option: A) 3 days B) 5 days C) 4 days D) 6 days E) 7 days

Rationale: "2 / 5 + ( 2 + x ) / 15 = 1 = > x = 7 days answer : e"
Answer: E