Question

Equations with rational coefficients

Lisa had $20.50 to spend on eight pens. After buying them she had $2.90. How much did each pen cost? ​

Answer 1

Each pen is 2.20

Explanation:

We first need to find the total cost of the pens

20.50 - 2.90 = 17.60

Now we can divide by the number of pens purchased.

17.60 / 8

2.20

Each pen is 2.20

Answer 2

$ 2.20

Explanation:

First, let us find the total cost of pens.

$ 20.50 - $ 2.90 = $ 17.6

And now let us find the cost per pen.

For that, let the cost of a pen be x.

Number of pens Cost

8 $ 17.6

1 x

Use cross multiplication and find the value of x.

8x = 1 × 17.6

8x = 17.6

Divide both sides by 8.

x = $ 2.2

Therefore,

Cost of a pen is $ 2.20