A general equation to use for this situation is y = mx + b.
For this question, we can assume that y is total cost, m is cost per balloon, x is the amount of balloons, and b as the service fee; so we can set the equation up:
y = (4.50)x + 12
And we can further plug in the total cost to find the number of balloons purchased for the party:
79.50 = (4.50)x + 12
Now we can solve for x (number of balloons):
67.50 = (4.50)x
x = 15
The total number of balloons purchased for the party is 15.
Solution
Given the question in the image, the following are the solution steps to answer the question.
STEP 1: Write the formula for slope

STEP 2: Pick two points
STEP 3: Find the unit price per cup
Since 4 cups cost $5, one cup will cost

Therefore, the answer is $1.25
Answer:
0.08
Step-by-step explanation: