90 students represent x percent of the boys at Jones Elementary School. If the boys at Jones Elementary make up 30% of the total school population of x students, what is x?	Choose the correct choice from the following answers
A) 125	B) 173	C) 225	D) 250	E) 500

Rationale: "90 = x / 100 * 30 / 100 * x = > x ^ 2 = 9 * 10000 / 3 = > x = 173 b"
Answer: B