so total money=m
cost=total money
cost=number of tshirts times cost per tshirt
subsitute
m=27 times cost per shirt
to solve for cost per 1 shirt, divide both sides by 27
[tex] \frac{m}{27} [/tex]=cost per 1 shirt
answer is 1 t-shirt costs [tex] \frac{m}{27} [/tex]