How to find the position function from the velocity function?

The velocity is the derivative of the position with respect to time, which is f′(t). Once you have that function, you set it to 0 and solve for t to find the time at which the velocity is zero, and then you can use that time to find the position of the object at that moment. I hope this helps

The clear answer is clearly 25 is very clear to me

Hnmmmn not sure