Question

A 5-mile cab ride costs $7.20. A 9-mile cab ride costs $11.60. Find a linear equation that models a relationship between cost c and distance d.
c = 1.44d + 4.40
d = 1.10c + 4.40
c = 1.29d + 1.70
c = 1.10d + 1.70

Answer 1

Let

d--------> the distance in miles

c-------> the cost in dollars

$A(5,7.20)\\B(9,11.60)$

Step $1$

Find the slope AB of the linear equation

we know that

the formula to calculate the slope between two points is equal to

$m=\frac{(c2-c1)}{(d2-d1)}$

substitute the values in the formula

$m=\frac{(11.60-7.20)}{(9-5)}$

$m=\frac{(4.40)}{(4)}$

$m=1.10$

Step $2$

Find the equation of the line with m and the point A

$A(5,7.20)\\m=1.10$

we know that

the equation of the line in the point-slope form is equal to

$c-c1=m*(d-d1)$

substitute the values

$c-7.20=1.10*(d-5)$

$c=1.10d-5.50+7.20$

$c=1.10d+1.70$

therefore

the answer is the option

c = 1.10d + 1.70

Answer 2

C - 7.2 = (11.6 - 7.2)/(9 - 4) (d - 5)
c - 7.2 = 4.4/4 (x - 5) = 1.1(d - 5)
c = 1.10d - 5.5 + 7.2
c = 1.10d + 1.70


The last option is correct.