Explanation:
Given that,
Maggie bought c CDs for $12 each, b books for $7 each, and a purse costing $24.
(a) Cost of c CDs = 12c
Cost of b books = 7b
Cost of p purse = 24p
Total amount = 12c+7b+24p
(b) Cost of 4 CDs = 12(4) = $48
Cost of 3 books = 7(3) = $21
Hence, this is the required solution.