The ratio of boarders to day students at a school was originally 5 to 12. However, after a number of new boarders join the initial 330 boarders, the ratio changed to 1 to 2. If no boarders became day students and vice versa, and no students left the school, how many new boarders joined the school? Choose the correct choice from the following:
A) 48 B) 66 C) 72 D) 80 E) 84
Let x be the number of new boarders.   The ratio changed from 5:12 up to 1:2 = 6:12.   330 / (330+x) = 5/6   x = 66   The answer is 66.
<result>B</result>
The ratio of boarders to day students at a school was originally 5 to 12. However, after a number of new boarders join the initial 330 boarders, the ratio changed to 1 to 2. If no boarders became day students and vice versa, and no students left the school, how many new boarders joined the school?