Answer:
b. Kathy
Step-by-step explanation:
We compare each of their score by how far away from the mean when in term of the standard deviation. Using the following formula

For John he is (85 - 75)/5 = 2.
For Kathy she is (80 - 50)/10 = 3.
Since Kathy is 3 standard deviation better than her class' average, while John is only 2's. We conclude that Kathy did better.
Gradient =2 because the slope is 2 units. Y-intercept = -2 because it crosses the y-line at -2.
x= -0.25 and 1.25
x = -0.5 and 1.5
x = 0 and 1
x = -0.375 and 1.625
Step-by-step explanation:
Given equation of the curve is

(i)
First equation 
Here y = 0
In x-axis the value of y = 0
The graph cuts the x-axis at(-0.25,0) and (1.25,0)
So, x= -0.25 and 1.25
(ii)

here y = 2
The line y= 2 cuts the curve at (-0.5,2) and (1.5,2)
So, x = -0.5 and 1.5
Given equation of the curve is

(i)


Here y = -1
The line y = -1 cuts the curve at (0,-1) and (1,-1)
So x = 0 and 1
(ii)

Here y = x+1
The line y -x =1 cuts the curve at (-0.375,0.5) and (1.625,2).
So x = -0.375 and 1.625
First, he paid 5/6 of the sticker price. He paid $29725 before the tax.
Then he paid a 7.25% sales tax. This can be found by multiplying $29725 by 1.0725
The final answer is C: $31,880.06