A take twice as much time as B or thrice as much time to finish a piece of work. Working together, they can finish the work in 3 days. B can do the work alone in? Select:
A) 18
B) 12
C) 11
D) 19
E) 114

Rationale: "suppose a , b and c take x , x / 2 and x / 3 respectively to finish the work . then , ( 1 / x + 2 / x + 3 / x ) = 1 / 3 6 / x = 1 / 3 = > x = 18 so , b takes 9 hours to finish the work . answer : a"
Answer: A