To complete bookshelves, a customer at your store needs to purchase vertical brackets to attach to the wall. the customer wants the shelving to be 9 feet high and 10 feet long. the wall brackets come in 48-inch and 60-inch sections. the 48-inch sections cost $12.95; the 60-inch sections cost $16.95. the brackets should be 1 foot from each end and no more than 24 inches apart. what will be the total cost of the brackets, before tax?

We are given with
height = 9 feet
length = 10 feet
wall brackets:
48-in costing $12.95
60-in costing $16.95
distance of brackets from ends = 1 foot
maximum distance between brackets= 24 inches

The brackets are
48/12 = 4 feet
and
60/12 = 5 feet

One of each must be used to cover the height of the shelf

The length of the shelf is
60 inch
subtracting 1 in from each side for the allowance
60 - 2 = 58 in
Dividing by 24 inches
58/24 = 2.41 ~ 3 

The total cost is
($12.95 + $16.95) * 3 = $89.7
The total cost of the brackets is $89.7