Question

Who’s right? And why?

Answer 1

Answer: Raymond is correct

The DJ charges $75 an hour.

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Explanation:

x = number of hours

y = total cost

The DJ does a 3-hour event for $275. This means one point is (x,y) = (3,275)

Another point is (5,425) because a 5-hour event costs $425.

Let's find the slope of the line through these two points.

$(x_1,y_1) = (3,275) \text{ and } (x_2,y_2) = (5,425)\\\\m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}\\\\m = \frac{425 - 275}{5 - 3}\\\\m = \frac{150}{2}\\\\m = 75$

The slope is 75, meaning that each time y goes up by 75, x goes up by 1.

Flipped around it means each time x goes up by 1, y goes up by 75.

This means each time we add on an extra hour, the cost goes up by $75.

The DJ charges $75 an hour. Raymond is correct.