A laser beam takes 15 ms to travel from a rocket to the reflective surface of a planet and back to the rocket. How far is the rocket from this planet's surface

Explanation:

It took 7.5 ms or for the laser beam to reach the planet's surface. Since the speed of light is , the distance is

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