Answer:
When we have a discount of X% of the original price, the new price is calculated as:
New price = (original price) - (original price)*(X%/100%)
In our case, let's define:
P = original price of the fishing pole
f = price of the fishing pole after the discount
X% = 20%
Then the equation for the price of the fishing pole is:
f = P - P*(20%/100%) = P - P*0.2 = P*(1 - 0.2) = P*0.8
f = 0.8*P
This means that the price after the discount is 0.8 times the original price.
I believe the fastest way to solve this problem is to take any two of the given points and to find the slope and y-intercept of the line connecting those two points.
Let's choose the 2 given points (-3,16) and (-1,12).
Going from the first point to the second, the increase in x is 2 and the increase in y is actually a decrease: -4. Thus, the slope of the line connecting these two points is m = -4/2, or m = -2.
Now use the slope-intercept formula to find the y-intercept, b.
One point on the line is (-3,16), and the slope is m = -2.
Thus, the slope-intercept formula y = mx + b becomes 16 = -2(-3) + b.
Here, b comes out to 10.
So now we have the slope and the y-intercept. Write the equation:
y = mx + b becomes y=-2x+10. Which of the four given answer choices is the correct one?
3x-10+2x=115
5x-10=115
5x=125
x=25
m<b=3(25)-10=65
m<C=2×25=50
