Question

Hello! Please help me with this question. I’ll mark brainly! Thank you :)

Answer 1

Answer:

$\Huge\boxed{\ 12.12}$

Step-by-step explanation:

In order to find how much credit is left after 92 minutes, we need to

1.  Figure out the equation that describes this graph (since we don't know the y-intercept)

2. Find the credit remaining after 92 minutes using the equation formed.

Figuring out the equation of this graph:

First things first is to figure out the slope of this graph. Since this is a linear function, the slope will remain constant, and we can note something about slope here.

The slope of a line will be it's change in x divided by its change in y, often referred to with a formula.

$\frac{\Delta y}{\Delta x}$

Since we know two points on this graph, we can find the changes in the x and y then divide for the slope.

Since minutes used is the x, and credit left is the y, we have two points.

(41, 19.26) and (68, 15.48).

• The change in y is -3.78, as $19.26-15.48=3.87$, and we decreased, so -3.78.
• The change in x is 27 as $68-41=27$, and we increased.

The slope will then be $\frac{-3.78}{27}$ which comes out to be -0.14.

Now that we know the slope, that means our equation will look something like $y = -0.14x+b$ - however, we still have b to solve for!

To solve for it, we can substitute one of our points in - let's do (41, 19.26) - to the equation and solve for b.

• $19.26 =-0.14 \cdot 41 +b$
• $19.26 = -5.74+ b$
• $b = 19.26+5.74$
• $b = 25$

Now that we know that b = 25, we can plug it into our equation, making the final equation that represents this scenario

$y = -0.14x+25$

Solving for 92 minutes

Now that we know the equation to our graph, we can substitute in 92 minutes as the x value to find our y value (credit left).

• $y = -0.14 \cdot 92 + 25$
• $y = -12.88+25$
• $y =12.12$

Therefore, after 92 minutes, the amount of credit left is $12.12

Hope this helped!