Setting: There are X students in the music class and Y students in the art class.

According to the meaning and known, there are:

x =(2/5)(y+58)…………………………( 1)

y =(3/7)(x+58)………………………………(2)

from( 1):5x-2y- 1 16 = 0..............(3)

From (2): 7y-3x-174 = 0 ............... (4)

(3)×3+(4)×5:( 15x-6y-348)+(35y- 15x-870)= 0

Finishing: 29y- 12 18=0

Solution: y=42 (person)

(3)×7+(4)×2:(35x- 14y-8 12)+( 14y-6x-348)= 0

Finishing: 29x- 1 160=0

Solution: x=40 (person)

A: There are 40 students in the music class and 42 students in the art class.