Honors Algebra
2-9 Weighted Averages- Motion
Name:______________________________
1. Two cars heading for Juneau, Alaska, along the same route, left a gas station at the same time.
Their average speeds differed by 12 km/hr. The faster car reached Juneau after 6 hours of travel
time. The slower car took an hour longer. Find the average speed of each car.
Let x =
Rate (
)
Time (
)
Faster Car
Slower Car
2. A fishing trawler radioed the Coast Guard for a helicopter to pick up an injured crew person. At
the time the helicopter left the Coast Guard station, the trawler was 660 km away heading
directly toward the station. If the average speed of the trawler was 30 km/h and that of the
helicopter was 300 km/h, how long did it take the helicopter to reach the trawler?
r(
)
t(
)
3. Using the butterfly stroke to swim the length of the pool, Eva averaged 1.5 meters per second.
Swimming back, she used the breast stroke and averaged 1.2 meters per second. The entire
swim took 1 minute and 15 seconds. How long was the pool?
r(
)
t(
)
HW: Motion Problem Practice
1. A commuter train traveling due north at 80 kilometers per hour passes a freight train traveling due
south at 70 kilometers per hour. How long after they pass each other will the trains be 25 kilometers
apart?
2. A ski lift carries a skier up a slope at the rate of 40 meters per minute. The skier returns from the
top to the bottom on a path parallel to the lift at an average rate of 880 meters per minute. If the
round-trip traveling time is 23 minutes, how fast does a skier go up the lift? What is the length of
the ski-slope?
3. In still water, Meg can row 6 kilometers per hour. However, on the Branch River it took her 4 hours
to row upstream to her friend’s cabin and only 2 hours to return. Find the rate at which the river
was flowing.
4. A helicopter traveling at an average speed of 225 kilometers per hour left San Jose 1 hour after a
train which had departed at 7:00 AM. If the helicopter overtook the train in 48 minutes (be
careful!), find the average rate of the train.