Question

Greg chose C as the answer. How might he have gotten that answer?

Answer 1

Given:

The equation is  

$-0.4x+0.05y-1.25=0$

Where, y is the total cost and x is the number of months.

To find:

The y-intercept of the line represented by this equation.

Solution:

We have,

$-0.4x+0.05y-1.25=0$

Isolate y variable.

$0.05y=0.4x+1.25$

Divide both sides by 0.05.

$y=\dfrac{0.4x+1.25}{0.05}$

$y=\dfrac{0.4x}{0.05}+\dfrac{1.25}{0.05}$

$y=8x+25$

Putting x=0, we get

$y=8(0)+25$

$y=0+25$

$y=25$

Therefore, the y-intercept of the given equation is 25 and the correct option is D.