Write a function for a river word problem

Question

My problem:

The river flows at 1.5 meters per second.

Write a rational function rule for the total time required to travel a distance $d$ downstream and back in a river flowing at a rate $v_r$.

I'm not really sure what it means with the $v_r$. Also, what does it mean if the velocity is equal to the speed of the river?

Would you solve this by doing

$$T=(v-1.5)d+(v+1.5)d?$$

Thank you.

Answer 1

For a river flowing at v ft/min, the distance d, travel in t min is d = vt.
The time it takes to travel a distance of d is t = v/d.

As no other means of propulsion are provided, the time it takes to return is unfathomable.