On a map the distance between two mountains is 312 inches. The actual distance between the mountains is 136 km. Ram is camped at a location that on the map is 42 inch from the base of the mountain. How many km is he from the base of the mountain?  Answers:
A) 14.83  B) 14.81  C) 14.8  D) 14.82  E) 18.3

Rationale: "explanation : since 312 inch = 136 km so 1 inch = 136 / 312 km so 42 inch = ( 136 ã — 42 ) / 312 = 18.3 km answer : e"
Answer: E