Question

A graph of the Soaring Cupcake’s cost per cupcake is shown below. The graph shows a relationship between the number of cupcakes purchased, n, and the total cost of the order, t. The Soaring Cupcake charges a $15 initial fee and then $3.00 for every cupcake purchased. What is the total cost for 15 cupcakes? What is the total cost for 10 cupcakes? How many cupcakes can you order for $30? Write a function rule in function notation for the situation using the variables t and n: A.) Does an input value of 4 make sense for this situation, why? B.) Does an input value of 5.2 make sense for this situation, why?

Answer 1

1) $60

2) $45

3) 5 cupcakes ;; function for situation is 30(n)=3n+15

3A) No

3B) No

Explanation:

the function is f(x)=3x+15 where x= cupcakes

To find total cost for 15 cupcakes, simply look at the graph or if you don't trust your eyeballing skills, you would calculate it by:

f(15)=3x+15 meaning plug 15 into the equation which equal $60

same for 10 cupcakes

f(10)=3(x)+15 equals $45

# of cupcake order for $30

using the graph we can see that for $30 we can purchase 5 cupcakes

the function for the situation is 30(n)=3n+15

A) No it would not make sense because after substituting 4 for the n, it does not equal to 30

B) Yes it would make sense because substituting 5.2 for n, it equal to $30.6 or $30