A can do 50% more work as B can do in the same time. B alone can do a piece of work in 20 hours. A, with help of B, can finish the same work in how many hours ? Choose the correct choice from the following: A) 12 B) 8 C) 13 1⁄3 D) 51⁄2 E) None of these
B alone can do a work in 20 hours.   ∴ A alone can do 3⁄2 of the work in 20 hours.   i.e., A alone can do the same work in 40⁄3 hours   ∴ (A + B)’s one hour’s work = 3⁄40 + 1⁄20 = 5⁄40 = 1⁄8   ⇒ A and B together can finish the whole work in 8 hours.   Answer 8
<result>B</result>
A can do 50% more work as B can do in the same time. B alone can do a piece of work in 20 hours. A, with help of B, can finish the same work in how many hours ?