12 persons can complete the work in 18 days. after working for 6 days, 4 more persons added to complete the work fast. in how many more days they will complete the work?  Choose the correct choice from the following answers: A) 10 days B) 9 days C) 8 days D) 7 days E) 6 days

Rationale: total work 12 * 18 = 216 units after 6 days work finished 6 * 12 = 72 units remaining work 216 - 72 = 144 units remaing days = 144 ( 12 + 4 ) = 9 days answer : b
Answer: B