The total cost of 4 similar books is $24 while each CD costs $2 more than each book. If Samuel bought 3 books and 17 CDs, what was the average amount he spent on each of the items? (Please put dollars in the first box and cents in the second box.)

$ .

Average = sum of the parts ÷ number of parts

Sum of the parts = the total cost of all the items

Number of parts = number of items

The cost of each book: $24 ÷ 4 = $6

The cost of each CD: $6 + $2 = $8

Therefore, the total cost of all items: $6 × 3 + $8 × 17 = $18 + $136 = $154

The number of items bought: 3 books + 17 CDs = 20 items

Therefore, the average spent on each item: $154 ÷ 20 = $7.70