Once you know the money from adult tickets and student tickets separately, what operation should you use to find the total amount of money collected?

Does "at least $300" mean the total is less than, greater than, or equal to $300? Which inequality symbol matches that idea?

Write your inequality using $a$ and $s$, then compare its left-hand side and inequality symbol with each answer option.

Let $x$ represent $a$ (adult tickets) and $y$ represent $s$ (student tickets). Type each option into its own line, replacing $a$ with $x$ and $s$ with $y$, for example: 6x + 10y >= 300, 10x + 6y <= 300, etc. Desmos will shade the solution region for each inequality.

Think of combinations that give exactly $300 in real life using the given prices (for example, all adults or all students). Compute such combinations and plot them as points, like (x, y) = (number of adult tickets, number of student tickets) in Desmos. These points should lie on the boundary line of the correct inequality (the line where the total equals $300).

Now test a point that clearly gives more than $300 (for example, more tickets than your exact-$300 combination). The correct inequality’s graph will shade the side that includes this “more than $300” point, because it represents totals at least $300.

Each adult ticket costs $10 and there are $a$ adult tickets, so the money from adult tickets is $10a$.

Each student ticket costs $6 and there are $s$ student tickets, so the money from student tickets is $6s$.

To get the total ticket sales, add the money from adult tickets and student tickets:

• Total money collected is $10a + 6s$.

"At least $300" means the total can be $300 or more.

So the inequality symbol you need is $\ge 300$ (greater than or equal to 300).

Put the total money expression together with the inequality for "at least $300":

This matches answer choice D.