Question 4333
Start by letting M = # of male students and F = # of female students.

Change the percents to equivalent decimals:  35% = 0.35 and 40% = 0.4

Now you can write ths system of equations:

0.35M + 0.4F = 369   The total number of students attending the ball game.
M + F = 980  The total number of students attending school.  Rewrite this as:
M = 980 - F and substitute into the first equation.

0.35(980 - F) + 0.4F = 369       Solve for F
343 - 0.35F + 0.4F = 369  Combine like-terms and subtract 343 from both sides.
0.05F = 26  Divide both sides by 0.05
F = 520  The number of female students.

M = 980 - F
M = 980 - 520 = 460  The number of male students.