If a person walks at 15 km/hr instead of 10 km/hr, he would have walked 15 km more. The actual distance traveled by him is?  Pick one
A) 30 B) 50 C) 15 D) 12 E) 20

Rationale: "let the actual distance traveled be x km . then , x / 10 = ( x + 15 ) / 15 x - 30 = > x = 30 km . answer : a"
Answer: A