Bunuel wrote:

Tough and Tricky questions: Work/Rate Problems.

A group of 4 junior lawyers require 5 hours to complete a legal research assignment. How many hours would it take a group of three legal assistants to complete the same research assignment assuming that a legal assistant works at two-thirds the rate of a junior lawyer?

A) 13

B) 10

C) 9

D) 6

E) 5

Kudos for a correct solution.Source: Chili Hot GMAT

one hr work of 4 lawyers is 1/5

then one hr work of 1 lawyer will be 1/20

given that assistant works at two-thirds the rate of a junior lawyer

therefore in one hr an assistant will complete 2/3 of 1/20 i.e 1/30 of work

then one hr work of a group of 3 assistants will be 3* 1/30 = 1/10

thus a group of 3 assistant will complete the work in 10 hours

[B]

_________________

Never Try Quitting, Never Quit Trying