Question

Josh received a gift card of $70 for a pizza restaurant. The restaurant charges $20 per pizza. Jessica received a gift card of $60 for a different pizza restaurant. The restaurant charges $15 per pizza.
Let x be the number of pizzas purchased.


Write an equation to show when the two cards would have the same amount of money left on them.

Answer 1

Let x be the number of pizzas purchased. For each card, write an expression for the amount of money left on the card after purchasing x pizzas.

For Keith

Keith received a gift card of $90 for a pizza restaurant. The restaurant charges $15 per pizza.

x numbers of pizza costs = $15x

Hence, the amount of money left on Keith's card after purchasing x pizzas =

$90 - $15x

For Mary,

Mary received a gift card of $110 for a different pizza restaurant. The restaurant charges $20 per pizza.

Hence, x number of pizzas cost =$20 × x

= $20x

Therefore, the amount of money left on Mary's card after she buys x pizzas =

$110 - $20x

Amount of money left on Keith's card in dollars = __________

Amount of money left on Mary's card in dollars=____________

Write an equation to show that the two cards have the same amount of money left on them [don't know how to do this part.

To find the equation that shows that the two cards have the same amount of money =

Equation 1 = Equation 2

$90 - 15x = $110 - 20x

Collect like terms

-15x + 20x = $110 - $90

5x = 20

x = 20/5

x = 4

Hence, anytime Keith and Mary buys 4 pizzas their gift card will have the same amount of money left on them.