In a certain boys camp, 20% of the total boys are from school A and 30% of those study science. If there are 35 boys in the camp that are from school A but do not study science then what is the total number of boys in the camp? Answers
A) 70
B) 245
C) 150
D) 35
E) 250

Rationale: "since 30 % of the boys from school a study science , then 70 % of the boys from school a do not study science and since 20 % of the total number of boys are from school a , then 0.2 * 0.7 = 0.14 , or 14 % of the boys in the camp are from school a and do not study science . we are told that this number equals to 35 , so 0.14 * { total } = 35 - - > { total } = 250 . answer : e ."
Answer: E