How much time does it take a person to walk 12km north at the velocity at a velocity of 6.5 km/hrs?

"6.5 km/hr" is not a velocity. It's just a speed, so

we don't know what direction he's walking.

If he happens to be walking north, then it takes him

(12 km) / (6.5 km/hr) = 1.846 ... hours (rounded).

If he's walking in any other direction, it takes him longer than that.

If the angle between north and the direction he's walking is

90 degrees or more, then he can never cover any northward

distance, no matter how long he walks.

I'm thinking this should actually go in the math section because you need to divide 12 by 6.5 to get the number of km/hour.