How you could calculate a time step (dt) if you have a vector of accumulative distance (ie the distance keeps adding every step) and an instantaneous velocity vector (ie the speed at that moment).

dt = ds/dv.

Explanation:

to calculate the time step if you have a vector of accumulative distance and instanteneous velocity vector can be expressed bellow

solution

ds = dv/dt

divide the step distance by the instantaneous velocity you will get the time step.

that it

dt = ds/dv.

so to calculate the time step having a vector that keeps adding every step and speed at that moment is this dt = ds/dv.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min