39 persons can repair a road in 12 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work? Choose the correct choice from the following:
A) 10  B) 13  C) 14  D) 15  E) 16
According to the chain rule,   M1 x T1 = M2 x T2   Therefore, 36 x 12 x 5 = 30 x 6 x X   X = 13   Hence, the number of days = 13.   ANSWER:13
<result>B</result>
39 persons can repair a road in 12 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work?