Question

Rosa has decided to sell pet rocks at an art fair for 5 dollars each. She has paid 50 dollars to rent a table at the fair and it costs her 2 dollars to package each rock with a set of instructions. For what number of sales will Rosa makes profit?

Answer 1

18 (or more)

Explanation:

Let's start off by creating an inequality:

Let "r" represent one pet rock

5r > 50 + 2r

Let's cancel out the 2r on the right side of the inequality by subtracting 2r from both sides:

5r > 50 + 2r

3r > 50

Now, to isolate r, we must divide both sides by 3:

3r > 50

r > 16.7

(Since we can't sell 16.7 pet rocks, we round up to 17)

r > 17

That means that Rosa has to sell at more than 17 pet rocks (so 18 or more pet rocks) to make profit.