Paul drove 225 miles to visit his parents. The graph below shows the distance traveled and the total time of the trip. Write and solve an expression to determine Paul's average speed from hour 1 to hour 4.

To find the average speed, we have to use the following formula
[tex] Average \ speed = \frac{D(4) -D(1)}{4-1} [/tex]
Where D(4) and D(1) are the distance at time t=4 hours and t=1 hour .
From the graph, we can say that
[tex] D(4) =225 miles , D(1) = 75 miles [/tex]
So average speed is
[tex] = \frac{225-75}{4-1} = \frac{150}{3} = 50 miles/hour [/tex]