A WORKS TWICE AS FAST AS B. IF B CAN COMPLETE A WORK IN 12 DAYS INDEPENDENTLY, THE NUMBER OF DAYS IN WHICH A AND B CAN TOGETHER FINISH THE WORK IS:
Answers.
A) 4 days B) 6 days C) 8 days D) 18 days E) none of these

Rationale: solution rates of worktio of raing of a and b = 2 : 1 . so , ratio of times taken = 1 : 2 ∴ a ’ s 1 day ’ s work = 1 / 6 b ’ s 1 day ’ s work = 1 / 12 ( a + b ) ' s 1 day ’ s work = ( 1 / 6 + 1 / 12 ) = 3 / 12 = 1 / 4 so , a and b together can finish the work in 4 days . answer a
Answer: A