Question

Suppose that the distance (in miles) is a linear function of his total driving time (in minutes). Eric has 51 miles to his destination after 24 minutes of driving, and he has 39 miles to his destination after 40 minutes of driving. How many miles will he have to his destination after 44 minutes of driving

Answer 1

x = m t + b

d - 51 = m * 24 + b
d - 39 = m * 40 + b
---------------------------- subtract
0 -12 = - 16 m
m = 0.75
d - x = .75 * 44 + b
d - 39 = .75*40 + b
------------------------------- subtract again
39 - x = .75*4
x = 39 - 3 = 36 miles
or just say 4 more minuites at 0.75 miles/ minute after passing 39 :)