Review #3

A bakery delivers cookies to offices.

*The bakery charges a $5 delivery fee.

*The bakery charges a total of $20 for delivering 12 cookies

*The bakery charges a total of $27.50 for delivering 18 cookies

Which equation represents the total charge in dollars, y, for a delivery of x cookies?

Hint: Can we create a table to enter into our Desmos calcuator to help us?

Remember to put y1 ~ mx1 + b in the second entry to see the slope and y-intercept.

User Icon for Bot GPT 4-o mini Bot GPT 4-o mini answered
2 hours ago

To determine the equation that represents the total charge in dollars (y) for a delivery of x cookies, we can analyze the information provided.

Given Information:

  1. The bakery charges a $5 delivery fee.
  2. The cost for delivering:
    • 12 cookies is $20
    • 18 cookies is $27.50

From the above, we can identify the total cost, which includes the delivery fee and the cost of the cookies themselves.

Step 1: Calculate Cost of Cookies

For 12 cookies:

Total charge = $20
Delivery fee = $5
Cost of cookies = Total charge - Delivery fee
Cost of cookies = $20 - $5 = $15
Cost per cookie = $15 / 12 = $1.25

For 18 cookies:

Total charge = $27.50
Delivery fee = $5
Cost of cookies = Total charge - Delivery fee
Cost of cookies = $27.50 - $5 = $22.50
Cost per cookie = $22.50 / 18 = $1.25

Step 2: Generalize the Information

From both cases, we can see that the cost per cookie is consistent at $1.25. Therefore, we can express the total charge (y) as a function of the number of cookies (x):

Step 3: Formulating the Equation

The total charge y for x cookies can be represented as: \[ y = 1.25x + 5 \] where:

  • 1.25 is the cost per cookie,
  • 5 is the delivery fee.

Step 4: Create Data Table

To verify, we can create a simple table with the values:

| Cookies (x) | Total Charge (y) | |-------------|-------------------| | 12 | 20 | | 18 | 27.50 | | 0 | 5 | (representing just the delivery fee)

Using the equation \(y = 1.25x + 5\):

  • For \(x = 12\): \(y = 1.25(12) + 5 = 15 + 5 = 20\) (correct)
  • For \(x = 18\): \(y = 1.25(18) + 5 = 22.5 + 5 = 27.50\) (correct)

Conclusion:

The equation representing the total charge in dollars, \(y\), for a delivery of \(x\) cookies is: \[ y = 1.25x + 5 \]