shirt=x
hats=y
3x+4y=96
2x+5y=99
(you'll have to get x in both equations to equal each other or y as well it doesn't matter which so:
6x+8y=192
6x+15y=297
-7y=-105
7y=105
y=15
3x+4y=96
3x+4x15=96
3x=96-60
x=36/3
x=12
a shirt is $12 hope it makes sense!!