The problem says the students needed to collect at least $240$ dollars. Does that mean the total money should be less than, greater than, or equal to $240$? Which inequality symbol matches that idea?

Once you know the expression for the total money and which inequality symbol matches "at least," combine them into one inequality and look for it in the answer choices.

In Desmos, use $x$ for $s$ and $y$ for $l$. Type the expression 4x + 6y to represent the total amount of money from $x$ small and $y$ large candles.

Type the equation 4x + 6y = 240. This line shows all $(x, y)$ pairs where the total money is exactly $240$ dollars.

Turn the equation into inequalities for different choices, like 4x + 6y >= 240 and 4x + 6y <= 240, and look at the shaded regions. The inequality that correctly represents the situation will shade all points where the total money $4x + 6y$ is $240$ dollars or more, not $240$ or less.

Each small candle costs $4$ dollars, and $s$ is the number of small candles.

• Money from small candles: $4s$.

Each large candle costs $6$ dollars, and $l$ is the number of large candles.

• Money from large candles: $6l$.

So the total amount of money collected from all candles is

"At least" $240$ means the amount is $240$ or more, not less than $240$.

In inequality symbols:

• "at least $240$" translates to $\ge 240$ (greater than or equal to $240$),
• not $\le 240$ (which would mean $240$ or less).

You already know:

• Total money collected is $4s + 6l$.
• This total must be $240$ or more, which means it should be $\ge 240$.

So we set up the inequality by making the total money $4s + 6l$ be greater than or equal to $240$:

Comparing with the answer choices, this matches choice D.