If you rent a car for one day and drive 225 miles, the cost is $80. If you drive 350 miles in one day, the cost is $105. Let cm) represent the cost, in dollars, of driving m miles: a) Find a linear function C(m) that fits the data. b) Use the function of part (a) to find how much it will cost to rent a car for one day and drive it 475 miles. Also, find the number of miles you can drive for $155.

Respuesta :

Answer:

a) [tex] (x_1 = 225, y_1 = 80) , (x_2 = 350, y_2 = 105) [/tex]

And we want to find a function:

[tex] C (m) = b_1 m + b_0[/tex]

We can find the slope with this formula:

[tex] b_1= \frac{105-80}{350-225}= \frac{25}{125}=0.2[/tex]

And then we can use the point  [tex] (x_1 = 225, y_1 = 80)[/tex] to find the intercept [tex] b_o[/tex] and we got:

[tex] 80 = 0.2*225 +b_0[/tex]

[tex] b_0 = 80-45 = 35[/tex]

So then the linear function is given by:

[tex] C(m) = 0.2 m + 35[/tex]

b) For this case we have that m = 475 so we can replace into the function to find the cost like this:

[tex] C(m =475) = 0.2*475 + 35 = 130[/tex]

And for the other case we have a cost of 155 and we want to find the number of miles associated so we can do this:

[tex] 155 = 0.2m + 35[/tex]

[tex] 155-35= 120 = 0.2 m[/tex]

[tex] m= \frac{120}{0.2}= 600 mi[/tex]

Step-by-step explanation:

For this case we can define the following notation:

m= represent the miles travelled

C= represent the cost

Part a

For this case we have the following two points given:

[tex] (x_1 = 225, y_1 = 80) , (x_2 = 350, y_2 = 105) [/tex]

And we want to find a function:

[tex] C (m) = b_1 m + b_0[/tex]

We can find the slope with this formula:

[tex] b_1= \frac{105-80}{350-225}= \frac{25}{125}=0.2[/tex]

And then we can use the point  [tex] (x_1 = 225, y_1 = 80)[/tex] to find the intercept [tex] b_o[/tex] and we got:

[tex] 80 = 0.2*225 +b_0[/tex]

[tex] b_0 = 80-45 = 35[/tex]

So then the linear function is given by:

[tex] C(m) = 0.2 m + 35[/tex]

Part b

For this case we have that m = 475 so we can replace into the function to find the cost like this:

[tex] C(m =475) = 0.2*475 + 35 = 130[/tex]

And for the other case we have a cost of 155 and we want to find the number of miles associated so we can do this:

[tex] 155 = 0.2m + 35[/tex]

[tex] 155-35= 120 = 0.2 m[/tex]

[tex] m= \frac{120}{0.2}= 600 mi[/tex]