12 men complete a work in 18 days. Six days after they had started working, 4 men joined them. How many days will all of them take to complete the remaining work ?  Choose the correct choice from the following answers: A) 10 days B) 12 days C) 15 days D) 9 days E) None of these
In 1 day, work done by 12 men = 1⁄18   In 6 days, work done by 12 men = 6⁄18 = 1⁄3   Remaining work = 2⁄3   m1 × d1 × w2 = m2 × d2 × w1   or 12 × 18 × 2⁄3 = 16 × d2 × 1   or d2 = 4×18×2/16=9days   Answer 9 days
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12 men complete a work in 18 days. Six days after they had started working, 4 men joined them. How many days will all of them take to complete the remaining work ?