Correct Answer - Option 5 : 60 km
Given:
Speed of person is 20 km per hour instead of 15 km per hour he can travel 20 km more distance.
Calculation:
Let exact distance be X km, Then
⇒ (X/15) = {(X + 20)/20}
⇒ 20X = 15X + 300
⇒ 5X = 300
⇒ X = 300/5 = 60 km
∴ The exact distance is 60 km.