Another useful strategy when solving word problems is to make a table of values.

Consider the following problem:

Leslie Massey works as an investment banker. One particular investment that her clients like earns 4.5% interest each year. Copy the table below into your notes and complete the amount of interest earned column for each investment listed, if the investor keeps his or her money in the investment for one year.

Use the equation I = Prt, where I represents the amount of interest, P represents the principal (amount of investment), r represents the interest rate (as a decimal), and t represents the amount of time (in years).

Amount of Investment	Amount of Interest
$1,500	$67.50
$2,500	$112.50
$3,500	$157.50
$4,500	$202.50

Practice

Fumiko works at a clothing store that is advertising 20% off all merchandise. Three customers' purchases are shown below.

1. 2 shirts, each with an original price of $25, and one skirt with an original price of $35
2. 2 sweaters, each with an original price of $30, and one pair of pants with an original price of $40
3. 1 pair of shoes with an original price of $45 and 1 pair of sandals with an original price of $25

Which of the customers saved at least $15?

Make a table of values showing each customer's purchase total, before discount or sales tax, and the amount of discount they received.

	Amount of Purchase	Amount of Discount
Customer I	$85	$17
Customer II	$100	$20
Customer III	$70	$14

Answer: Customer I and Customer II

Mara needs to mail a large envelope that weighs 1 pound 3 ounces. The first ounce costs $0.95, and each additional ounce costs $0.20. How much in postage will Mara pay to mail the envelope?

Use the grid below to record your answer. Type your answer in the boxes in front of and behind the decimal. Click inside each box to enter the numeral that belongs in the box. Click the bubble beneath the numeral to shade the bubble that matches the numeral.Incorrect portions of your answer will be shaded gray.