A man's speed with the current of a river is 15 km/hr and the speed of the current is 2.5 km/hr. What is the man's speed against the current?
ক
8.5 km/hr
খ
9 km/hr
গ
10 km/hr
ঘ
12.5 km/hr
ঙ
None
সঠিক উত্তর: 10 km/hr