For a fundrasier, the Best Buddies club sold t-shirts. The adult shirts were $15 per shirt and the youth shirts were $12 per shirt, and they made a total of $330 on the shirts. If they sold a total of 26 shirts, how many of each did they sell?

I don't understand this, so please show work.

2 answers

A + Y = 26, so Y = 26 - A

15A + 12Y = 330

Substitute 26-A for Y in second equation and solve for A. Insert that value into the first equation and solve for Y. Check by inserting both values into the second equation.
I don't understand the substitute part.