7o:
date:
subject: physics
a car drove 3/4 of the total time at speed of 90 km/h and 1/4 of the total time at
speed of 50 km/h. what was its average speed?

i think the answer is a, hope this is right, that would be my best guess.

truck y has a greater velocity than truck x.

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