Problem of the Week 24

A car travels at 80 kilometers per hour for 40 kilometers, 72 kilometers per hour for 48 kilometers, and then 96 kilometers per hour for 32 kilometers.  What is the average rate of speed over the entire trip?


Alternate Problem 24

A circular race track is 35 feet wide.  The inside length of the track (near the railing) is 1 mile.  Suppose as horses run around the track, the outer horse is 30 feet from the inner horse.  How much farther must the outer horse run?  What is the percent increase over 1 mile?


Extension Problem 24

A car travels d1 kilometers at s1 kilometers per hour.  Then, it travels d2 kilometers at s2 kilometers per hour.  Finally, it travels d3 kilometers at s3 kilometers per hour.  Write a formula for the average rate of speed, S, over the entire trip.