Charlotte has 24 postage stamps.

Question

Charlotte has 24 postage stamps. Some of the stamps are 28-cent stamps, and the rest are 44-cent stamps. If the total value of the stamps is $9.12, how many of each type of stamp does Charlotte have?

Answer 1

Hi Leigh, let x represent the 28-cent stamps and y represent the 44-cent stamps. Set up a system of equations and solve.

Equation 1, number of stamps sold:

x + y = 24

Equation 2, cost of the stamps:

.28 * x + .44 * y = 9.12

Solve equation 1 for x and substitute:

x + y = 24

x = 24 - y

.28 * (24 - y) + .44 * y = 9.12

6.72 - .28y + .44y = 9.12

Combine terms:

.16y = 2.4

Divide both sides by .16:

y = 15

15 44-cent stamps were sold.

Substitute for y in equation 1:

x + 15 = 24

x = 9

Nine 28-cent stamps were sold.

Questions?