Question

. Hernandez bought 18 pens for her class. Highlighters cost $3 each, and gel pens cost $2.50 each. She spent a total of $50. Use a system of equations to find the number of highlighters and gel pens Mrs. Hernandez bought. Enter your answers in the boxes.

Answer 1

Before we solve for anything, let's assign variables for highlighters and gel pens. Highlighters can be 'h,' and gel pens can be 'g'.

We can make two equations from what we've been given so far. Since we know that Hernandez bought 18 pens, we know that:

h + g = 18

And since we know the cost of an individual gel pen and highlighter as well as the total price, we can make another equation:

3h + 2.50g = 50

We can simplify the first equation by keeping only one variable on one side:

h + g = 18
h = 18 - g

Now that we have a value for h, we can assign it to the second equation:

3h + 2.50g = 50
3(18 - g) + 2.50g = 50
54 - 3g + 2.50g = 50

Simplify:
-0.50g = -4
0.5g = 4
5g = 40
g = 8

Put this value into the equation we made earlier:

h = 18 - g
h = 18 - 8
h = 10

Hernandez bought 10 highlighters and 8 gel pens.