Question

A 2-mi cab ride costs $1.70. A 7-mi cab ride costs $3.70. Find a linear equation that models cost c as a function of distance d.
a.
c = 0.53d + 0.90
b.
c = 0.85d + 2.00
c.

c = 0.40d + 0.90

d = 0.40c + 2.00

Answer 1

c = m d + b

1.7 = 2 m + b
3.7 = 7 m + b
===================
-2 = -5 m
m = 2/5
so
c = (2/5) d + b
1.7 = (2/5)2 + b
b = 1.7 - .8 = .9
so
c = (2/5) d + 9/10
or
10 c = 4 d + 9