The sum of number of boys and girls in a school is 100. If the number of boys is x, then the number of girls becomes x% of the total number of students. The number of boys is?  Choose the correct choice from the following answers:
A) 50
B) 40
C) 60
D) 100
E) 70

Rationale: "we have x + x % of 100 = 100 x + x / 100 * 100 = 100 2 * x = 100 x = 50 answer is a"
Answer: A