However, when is the best time to fill a balloon? Helium has a tendency to escape from any opening in the balloon and will eventually deflate. This means that you should never wait until your event starts to inflate your balloons.

The small, individual helium molecules can escape through the tiny holes in the latex far more easily than the conjoined oxygen or nitrogen molecules can. ... This is why your helium balloons deflate faster than the ones you fill with air.

Explanation:

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