Question 224725
A car travels at 80mph for 40 miles, 72mph for 48miles, and then 96mph for 32 miles. What is the average rate of speed over the entire trip?
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40 miles at 80 mph takes 30 minutes
48 miles at 72 mph takes 40 minutes
32 miles at 96 mph takes 20 minutes
------120 miles in 90 minutes
= 4/3 miles/minute
= 80 mph