If 10 men and 2 boys working together, can do nine times as much work per hour as a man and a boy together. Find the ratio of the work done by a man and that of a boy for a given time?  Choices
A) 7:5  B) 7:3  C) 7:8  D) 7:1  E) 7:2
10M + 2B = 9(1M + 1B)   10M + 2B = 9M + 9B   1M = 7B   The required ratio of work done by a man and a boy = 7:1   Answer:7:1
<result>D</result>
If 10 men and 2 boys working together, can do nine times as much work per hour as a man and a boy together. Find the ratio of the work done by a man and that of a boy for a given time?