4x < $75
*I did not consider the GC of $25 because Chet already spent it before buying 4 work shirts. His budget for the work shirts is only $75.
4x < $ 75
÷4 ÷4
x < $18.75
Each shirt must cost a maximum of $18.75 so that Chet will not go over budget. Any work shirt bought with a price lower than $18.75 will be better for Chet, budget wise.