36 men can complete a piece of work in 18 days. In how many days will 72 men complete the same work ?  Choose the correct choice from the following answers
A) 24 B) 17 C) 18 D) 9 E) 11
Explanation:   Less Men, means more 9ays {Indirect Proportion}   Let the number of days be x   then,   72 : 36 :: 18 : x   x = 9   Answer: 9) 9 days
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36 men can complete a piece of work in 18 days. In how many days will 72 men complete the same work ?