15% = 15/100 = 0,15
<span>total ticket sales = </span>$375 : 0.15 = $2,500
See the attached picture:
As given m is a midpoint of ab. So am is half of ab.
So we can write

As given am = 3x+3 , ab = 8x - 6.
So





So x = 6.
So length of am = 3x+3 = 3*6 + 3 = 21
I got x < 2 for the inequality
Look at the image for more information