If 12 men and 16 boys can do a piece of work in 5 days; 13 men and 24 boys can do it in 4 days, then the ratio of the daily work done by a man to that of a boy is?	Options: A) 1:1 B) 2:1 C) 3:1 D) 4:1 E) 5:1
B   2:1   Let 1 man's 1 day work = x and 1 boy's 1 day work = y.   Then, 12x + 16y = 1/5 and 13x + 24y = 1/4   Solving these two equations, we get:   x = 1/100 and y = 1/200   Required ratio = x:y = 1/100 : 1/200 = 2:1.
<result>B</result>
If 12 men and 16 boys can do a piece of work in 5 days; 13 men and 24 boys can do it in 4 days, then the ratio of the daily work done by a man to that of a boy is?