## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$87.5$ miles per hour
At 3 PM, the train was around 275 miles from Denver. By 5 PM, the train was 450 miles from Denver The increase in distance from Denver is: $=450-275=175$ miles The elapsed time from 3 PM to 5 PM is 2 hours. Thus, the average rate is: $=\dfrac{175\text{ miles}}{2 \text{ hours}}=87.5$ miles per hour