Question

Kiyo bought a pizza for $12.75 and four medium drinks at Paola’s pizza. Define a variable and write an expression to represent the total amount of money he spent. Then find the total cost if one drink costs $3

Answer 1

Y = total amount of money spent
x = cost of one drink

So our expression is:
4x + 12.75

4x stands for 4 drinks times x price of one drink
The 12.75 is a one time fee for the pizza, since Kiyo isn't buying multiple pizzas.

The problem also asks us to find the total price, so we write an equation:

$y = 4x + 12.75$
We insert what x is which in this case is $3
$y = 4(3) + 12.75$
Order of Operations tells us to multiply first:
$y = 12 + 12.75$
Now add your values:
$y = 24.75$
Therefore, Kiyo spent a total amount of 24.75 at Paola's pizza.

Let's check our problem just in case:

$24.75 = 4x + 12.75$
Since we now know what y is equal to, we can plug that into our original equation and check just to verify

We should subtract 12. on both sides of the equation because of inverse operations:

$24.75 - 12.75 = 12.75 - 12.75 + 4x$
We are left with:

$12 = 4x$
We divide:
$\frac{12}{4} = \frac{4x}{4}$
Our result is:
$3 = x$
Which checks out because each drink was in fact, $3 dollars as stated in the word problem. Hope that was thorough enough.