Jenny bought 6 cookies and 6 cupcakes at the bakery. The cookies were $1.50 each, but she cannot remember how much each cupcakes was. She paid $21 total. How much was each cupcake?
The cost of the cookies was 6 * $1.50 = $<<6*1.5=9>>9.
Jenny paid $21 - $9 = $<<21-9=12>>12 for cupcakes.
The cost of 1 cupcake is $12 / 6 = $<<12/6=2>>2. Answer: \boxed{2}.