Answer:
$80 was on the gift card to begin with
Step-by-step explanation:
Let the initial money be x
Peter spent (1/2)*x
Peter added 10
<em>Before adding more money on the gift card Peter had x -(1/2)x left on the gift card which is (1/2)x</em>
<em>After loading more money Peter had (1/2)x + 10</em>
(1/2)x = 40 <em>(money spent by Peter)</em>
x/2 = 40
x = 80
Try plugging in 4,6, and -7 into the x's
All of them are wrong its 91 but if you want click or circle 90
72.5%
You can get this by dividing the new price by the original price and then multiplying by 100.
To find the slope of the line, use the rise over run formula:

Take any two points from the line and plug them into the formula.
(0,0) and (10, 5)

The slope of the line is 0.5.
Using the form y = mx, the following equation will be your answer: