We are given expression:
2a+1.5b, where a is the number of cupcakes and b is the number of cookies at a bake.
a is being multiplied by 2 and b is being multiplied by 1.5.
Therefore,
A. The cost for 1 cupcake is $2 and the cost for 1 cookie is $1.5.
B. The total cost for 6 cupcakes and 6 cookies is
2×6 + 1.5×6 = 12 + 9 = $21 .
C. Cost of 7 cupcakes and 4 cookies = 2×7 + 1.5 × 4 = 14 +6 = $20 .
Yes, $20 is enough to buy 7 cupcakes and 4 cookies.