SOLUTION: a taxicab ride that is 2 miles long cost $7. One that is 9 miles long cost $24.50. Write an equation relating cost to length of ride.

Algebra ->  Graphs -> SOLUTION: a taxicab ride that is 2 miles long cost $7. One that is 9 miles long cost $24.50. Write an equation relating cost to length of ride.      Log On


   

Question 108745: a taxicab ride that is 2 miles long cost $7. One that is 9 miles long cost $24.50. Write an equation relating cost to length of ride.
Answer by HyperBrain(694) About Me  (Show Source):
You can put this solution on YOUR website!
Let x=the x-coordinate
____y=the y-coordinate

Here, I want the x-coordinate to be the no. of miles and the y-coordinate to be the price. So, the points are (2,7) , (9,24.50)

Let's find the slope

slope=%28y-increment%29%2F%28x-increment%29=%2824.50-7%29%2F%289-2%29=17.50%2F7=2.5
Now, let's use the slope-intercept form y=mx%2Bb where m=slope and b=y-intercept
m=2.5 but b is unknown. So, let's use (2,7) for x=2 and y=7
y=mx%2Bb
7=2.5%2A2%2Bb
7=5%2Bb
7-5=5-5%2Bb
2=0%2Bb
0%2Bb=2
b=2
Thus, the equation is y=2.5x%2B2

Which is interpreted as "the price is calculated by multiplying the no. of miles by 2.5 and by adding 2 to the result"
Graph:
graph%281000%2C1000%2C-20%2C20%2C-20%2C20%2C2.5x%2B2%29

Power up,
HyperBrain!