You are given two x and y pairs: (100,45) and (570,162.5)
First solve for the slope, m.
m = (162.5 - 45) / (570 - 100)
m = 117.5 / 470
m = 0.25
Not only is "m" the slope but it is the rate (dollars per minute) in the question. So it's 25 cents per minute to use the phone.
After imputing "m" the linear equation looks like this:
y = 0.25x + b
Use either point as (x,y) to solve for the y-intercept "b". I'll use (100,45)
45 = 0.25(100) + b
45 = 25 + b
45 - 25 = b
20 = b
Not only is "b" the y-intercept but it is also always the flat fee added on to linearly increasing cost questions like this.
Final equation is:
y = 0.25x + 20
Part B.) If 939 minutes are used. Just put that in for x and solve for y.
y = 0.25(939) + 20
y = 234.75 + 20
y = 254.75
20% * 158.08 =31.616
or
20% * £158.08 =48.1005824
Answer:
15% markdown
Step-by-step explanation:
In order to find the markdown, take the lowered price and place it in a fraction as the numerator, and the initial price as the denominator. This looks like:
with this fraction, we're going to multiply it by 100, with an equation looking like this,
×
once we multiply(typically using a calculator, though manually is possible of course) we get 85.
In order to find the markdown price however, we need to subtract 85 from 100, getting 15. This is the markdown price, because it's the percentage of the initial whole that the price went down by. Can check by finding 15% of 975, which is 828.75
