A mountain slope and a skier make up a closed system with 21,800 J of energy. When the skier starts her descent down the mountain, the mechanical
energy of the system is 19,500 J. By the time she reaches the bottom, the
system's mechanical energy has fallen to 18,230 J. How much of the total
energy is transformed into thermal energy?

the second one and the forth one are in the purple because they are opinions and the rest are in the yellow

explanation:

i believe the answer is a hope it and is correct

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