Question

A 3 mi cab ride cost $3.00 . A 6 mi can ride cost $4.80 find a linear equation that modes cost c as a function of distance d.

Answer 1

c = 0.6d + 1.2

Explanation:

Use distance as the independent variable and cost as the dependent variable. Each point (x, y) is (distance, cost).

The 3 mile ride for $3.00 gives you point (3, 3).

The 6 mile ride that cost $4.80 gives you point (6, 4.8).

Now you need to find the equation of the line that passes through points

(3, 3) and (6, 4.8).

y = mx + b

m = slope = (y2 - y1)/(x2 - x1) = (4.8 - 3)/(6 - 3) = 1.8/3 = 0.6

Use point (3, 3).

y = 0.6x + b

3 = 0.6(3) + b

3 = 1.8 + b

b = 1.2

The equation is

y = 0.6x + 1.2

Use c for cost and d for distance to get

c = 0.6d + 1.2