If you travel from Yakima to Ellensburg (Yakima to Ellensburg is 50 miles) with a speed of 60 miles/hour for half of the

trip and 80 miles/hour the other half of the trip. What is your Average speed? HINT: It is not 70 miles/hour:

68.57 mile/hour

Explanation:

The distance from Yakima to Ellensburg is 50 miles and you travel with 60 miles/hour for the first 25 miles, then 80 miles/hour for the last 25 miles. The easy way to solve this question is to find the total time needed to travel.

The time needed to travel 25 miles with 60 miles/hour speed will be: 25 miles / (60 miles/hr) = 0.42 hr

The time needed to travel 25 miles with 80 miles/hour speed will be: 25 miles / (80 miles/hr) = 0.31 hr

Total time needed to travel 50 miles will be: 0.41 hr + 0.31hr = 0.73 hr

The average speed will be:

average speed = sum of travel distance / sum of time needed = 50 miles / 0.73hr = 68.57 mile/hr