Reuben has 31 miles remaining after 34 minutes of driving. How many miles will he remaining after 54 minutes of driving?

Question

when Graphed the function gives a line with a slope of -0.7

 

Answer 1

y = mx + b

m= -0.7

(34,31) is on the line

31 = -0.7 (34) + b

b=54.8

 

now substitute x= 54 to calculate y.

 

Question's wording is faulty--read before submitting!  The answer may be 17 miles remaining but you should CHECK all work.

Answer 2

Time is always independent.

 

Let x = number of minutes

Let y = number of miles remaining

 

Since your slope is known and your first point is known, we can use the point-slope form of a line to find the equation of the line.

 

y = -0.7(x - 34) + 31

 

y = -0.7x + 23.8 + 31

 

y = -0.7x + 54.8

 

 

Evaluate y when x=54.  This will give you the remaining miles after 54 minutes.