A work as fast as B. If B can complete a work in 24days independently,the number of days in which A and B can together finish the work in? Pick one.
A) 2 days
B) 3 days
C) 8 days
D) 5 days
E) 6 days

Rationale: "ratio of rates of working of a and b = 2 : 1 ratio of times taken = 1 : 2 a ' s 1 day work = 1 / 12 b ' s 1 day work = 1 / 24 a + b 1 day work = 1 / 12 + 1 / 24 = 3 / 24 = 1 / 8 a and b can finish the work in 8 days answer is c"
Answer: C