Question 1203619: A passenger plane left Tokyo and flew toward Las Vegas. Two hours later a cargo plane left flying 70 km/h faster in an effort to catch up to it. After five hours the cargo plane finally caught up. Find the passenger plane's average speed.
Found 4 solutions by Edwin McCravy, greenestamps, ikleyn, mccravyedwin:
Answer by Edwin McCravy(20056)   (Show Source):
You can put this solution on YOUR website! A passenger plane left Tokyo and flew toward Las Vegas. Two hours later a cargo
plane left flying 70 km/h faster in an effort to catch up to it. After five
hours the cargo plane finally caught up. Find the passenger plane's average
speed.
Let the passenger plane's average speed be r. Then the cargo plane's average
speed is r+70.
The cargo plane's time is 5 hours. The passenger plane's time is 2 hours more,
or 7 hours. Rate x Time = Distance. Their distances are equal when the cargo
plane catches up.
| Rate | Time |Distance|
Passenger plane| r | 7 | 7r |
Cargo plane | r+70 | 5 |(r+70)5 |
7r = (r+70)5
7r = 5r+350
2r = 350
r = 175 km/h
Edwin
Answer by greenestamps(13200)  (Show Source):
You can put this solution on YOUR website!
It took 5 hours for the cargo plane to catch up to the passenger plane, flying 70 km/h faster.
That means the cargo plane made up 5*70 = 350 km in 5 hours.
That means 350 km was the distance the passenger plane covered in its first two hours of flight.
That means the speed of the passenger plane was 350/2 = 175 km/h.
ANSWER: 175 km/h
Answer by ikleyn(52793)  (Show Source):
You can put this solution on YOUR website! .
I would like to leave one comment, regarding this problem.
The distance from Tokyo (the capital of Japan) to Las Vegas (the city in the US)
is 8900 kilometers (according to the Internet).
So the time of such a flight is  , or about 50 hours.
It is written for the future generations of students, who will read this post,
in order for they could estimate, if this problem is realistic or not.
Actually, a Math problem doesn't have to be realistic; but this one, concretely,
naming the cities, pretends to be realistic, however fails.
Answer by mccravyedwin(407)  (Show Source):
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