90 students represent x percent of the boys at Jones Elementary School. If the boys at Jones Elementary make up 60% of the total school population of x students, what is x?  Pick.
A) 122
B) 150
C) 225
D) 250
E) 500

Rationale: "90 = x / 100 * 60 / 100 * x = > x ^ 2 = 9 * 10000 / 6 = > x = 122 a"
Answer: A