First, calculate how many jumps per minute, and the formula is: 90 ÷ 1.5 = 60 メ.

Then calculate how many times to jump in 2.4 minutes: 2.4× 60 =144.

12,

To get the average level and compare their average values, first calculate the fourth grade:

(2 1+30+52+37) (4 = 35).

Calculate the fifth grade:

(32+38+53+35) (4 = 39.5).

Comparing the two averages, it is 35 < 39.5.

So the general level of the fifth grade is higher (because of the formula)

I hope I can help you.