Cereal A is 11% sugar by weight, whereas healthier but less delicious Cereal B is 2% sugar by weight. To make a delicious and healthy mixture that is 4% sugar, what should be the ratio of Cereal A to Cereal B, by weight?
Choose the correct choice:  A) 2 : 5  B) 1 : 3  C) 2 : 7  D) 3 : 4  E) 1 : 5

Rationale: "2 % is 2 % - points below 4 % and 11 % is 7 % - points above 4 % . the ratio of a : b should be 2 : 7 . the answer is c ."
Answer: C