Answer with explanation:
Original Price of Single T shirt = P dollars
After , Selling 20 T-Shirts
Money Earned= (20 P - 60) Dollars
Selling Price of Single T -Shirt
[tex]=\frac{\text{Selling Price of 20 T -Shirt}}{20}\\\\=\frac{20P-60}{20}\\\\=\frac{20*(P-3)}{20}\\\\=P-3[/tex]
Selling Price of Single T shirt = (P -3) Dollars