Slope and rate of change on card 7 an 8

Card 7

The hourly rate of change/slope is $75 per hour.

Card 8

Frastastic is charging $0.48 per ounce.

Step-by-step explanation:

Card 7

Lets take the set up fee as "$" and,

Hourly rate as $per hour.

Now we can write equations for 3 hour event and 5 hour event.

<------- (1)

<------- (2)

Now we need to solve the simultaneous equations to find and .

Subtract (1) from (2)

⇒

So the hourly rate of change/slope is $75 per hour.

Therefore, Raymond is right.

Card 8

You can take Amount (oz) as x values and Cost as y values and plot a graph.

Then the Slope of the graph will give you the rate Frastastic is charging per yogurt.

Slope of a linear graph is given by the following equation;

Slope(m)=

Slope(m)=

Slope(m)=

Slope(m)=

Therefore, Frastastic is charging $0.48 per ounce.

This is less than $0.50 per ounce charged by Fromazing. Therefore, Sterling is right.