If a person walks at 15 km/hr instead of 5 km/hr, he would have walked 20 km more. The actual distance traveled by him is? Choose the correct answer:
A) 50 km B) 76 km C) 18 km D) 10 km E) 97 km

Rationale: "let the actual distance traveled be x km . then , x / 5 = ( x + 20 ) / 15 10 x - 100 = > x = 10 km . answer : d"
Answer: D