If all 8 tickets were sold at the minimum price of $12, what would the total cost be? Multiply $12$ by $8$.

If all 8 tickets were sold at the maximum price of $15, what would the total cost be? Multiply $15$ by $8$.

Once you know the smallest and largest possible total costs, check which answer choices fall between those two values (including the endpoints).

In Desmos, type 8*12 on one line and 8*15 on another line. Note the two output values; these are the minimum and maximum possible total costs for 8 tickets.

Look at the numerical outputs from Desmos and then check which of the given answer choices is between these two values (including the endpoints). That choice is a possible total cost for 8 tickets.

The price of each ticket is between $12$ and $15$, including both ends. In inequality form, this is:

You are buying 8 tickets, so the total cost is the sum of 8 ticket prices, each in this range.

To get the smallest total cost, imagine all 8 tickets cost the minimum price, $12$ dollars each.

So, the total cost cannot be less than $96$ dollars.

To get the largest total cost, imagine all 8 tickets cost the maximum price, $15$ dollars each.

So, the total cost cannot be more than $120$ dollars.

From the previous steps, the total cost for 8 tickets must be between $96$ and $120$ dollars, inclusive.

Check each choice:

• $90$ is less than $96$.
• $99$ is between $96$ and $120$.
• $124$ is more than $120$.
• $140$ is more than $120$.

Only $99$ is in the allowed range, so the correct answer is 99.