Question

Alexis has a stamp collection of 3 cent stamps and 8 cent stamps. She has 1 less 8 cent stamps as 3 cent stamps. If the collection has a face value of 69 cents, how many of each does she have?

She has ____ 3 cent stamps and _____ 8 cent stamps.

Answer 1

She has seven 3 cents stamps and six 8 cents stamps.

Explanation:

7*3 = 21

6*8 = 48

48 + 21 = 69

Answer 2

Answer: She has SEVEN 3 cent stamps and SIX 8 cent stamps.

Explanation:

Let be "x" the number of 8 cent stamps and "y" the number of 3 cent stamps.

Set up the following system of equations:

`\left \{ {{x=y-1} \atop {8x+3y=69}} \right.`

Substitute the first equation into the second one and the solve for "y":

`8(y-1)+3y=69\\\\8y-8+3y=69\\\\11y=77\\\\y=7`

Substitute the value of "y" into the first equation:

`x=7-1\\\\x=6`