Sure thing!
So, because the pizza was $16 and the price was split among two people, that means Jae spent $8 on the pizza.
Jae spent $48 total (both Jet Ski and Pizza), so subtract $8 from that to get the amount he paid for the Jet Ski: $40
Now, since the rental fee was divided evenly among n amount of friends, divide $120 by $40 (120/40) and your answer should be 3.
n = 3
There were 3 friends who split the rental fee of the Jet Ski.
Hoped this helped!