The ratio of spinsters to cats is 2 to 9. If there are 42 more cats than spinsters, how many spinsters are there?  Choose the most appropriate option:
A) 9  B) 10  C) 11  D) 12  E) 13

Rationale: "let 2 x be the number of spinsters . then 9 x is the number of cats . 9 x - 2 x = 42 x = 6 and the number of spinsters is 2 ( 6 ) = 12 . the answer is d ."
Answer: D