Question

A car travels at a constant speed. What is the car's speed between checkpoints, expressed as a unit rate? Checkpoint A 1:00 PM Total miles driven 120. Checkpoint B 3:00 PM Total miles driven 208.

Answer 1

Average speed  

Average speed between the checkpoints  
distance between the checkpoints
divided by
time between the checkpoints. 

Distance between the checkpoints = 
(mileage at B) minus (mileage at A)
=(208)-(120)  =  88 miles .

Time between the checkpoints = 
time at - time at A

=(3:00 PM) - (1:00 PM) =  2 hours .

Average speed between the checkpoints  =  

(88 miles) / (2 hours)

=44 miles per hour .