15 men and 12 boys finish a job in 11 days, 13 men and 13 boys finish it in 10 days. 10 men and 10 boys shall finish it in how many days?  Choose the correct choice from the following answers.
A) 18
B) 17
C) 12
D) 11
E) 12
13 M + 4 B ----- 11 days   9 M + 9 B ------- 10 days   12 M +12 B -------?   117 M + 36 B = 108 M +108 B   72 B =9 M =&gt; 1 M = 8 B   104 B + 4 B = 108 B ---- 11 days   96 B + 12 B = 108 B -----? =&gt; 11 days   Answer: 11
<result>D</result>
15 men and 12 boys finish a job in 11 days, 13 men and 13 boys finish it in 10 days. 10 men and 10 boys shall finish it in how many days?