8.88 I think. Hope this helps :)

each shirt costs $6

The percent markup is about 66.7%
X=6 because
9-6=3
X=3 because
2•3=6
X=2 because
1.5 or 1 1/2 • 2 = 3
Not sure if this was what you needed or not!
4n - 9 + 3n + 5 + n = 68
combine like terms
8n - 4 = 68
addition property of equations
8n = 72
division property of equality
n = 9
SIDES:
n = 9
3n + 5 = 32
[ 3(9) + 5 = 32 ]
4n - 9 = 27
[ 4(9) - 9 = 27 ]