# Algebra World Problem: What is the average speed of the plane...?

#### Vega

##### New member
Hopefully this is in the right place...

Here is my problem, thanks in advance...!

"Let's say a jet leaves Los Angeles and flies straight across the country to New York City. Thanks to the jet stream, the jet enjoys a brisk tailwind and averages 600mph for the 3000 mile distance. On the return flight, back to L.A., the jet encounters the same jet stream, this time of course as a headwind. Therefore, the jet averages only 4000mph for the 3000 mile return trip.

What is the average speed of the plane for the entire round-trip flight or journey"?

#### Subhotosh Khan

##### Super Moderator
Staff member
Hopefully this is in the right place...

Here is my problem, thanks in advance...!

"Let's say a jet leaves Los Angeles and flies straight across the country to New York City. Thanks to the jet stream, the jet enjoys a brisk tailwind and averages 600mph for the 3000 mile distance. On the return flight, back to L.A., the jet encounters the same jet stream, this time of course as a headwind. Therefore, the jet averages only 4000mph for the 3000 mile return trip.

What is the average speed of the plane for the entire round-trip flight or journey"?
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#### stapel

##### Super Moderator
Staff member
"Let's say a jet leaves Los Angeles and flies straight across the country to New York City. Thanks to the jet stream, the jet enjoys a brisk tailwind and averages 600mph for the 3000 mile distance. On the return flight, back to L.A., the jet encounters the same jet stream, this time of course as a headwind. Therefore, the jet averages only 4000mph for the 3000 mile return trip.

What is the average speed of the plane for the entire round-trip flight or journey"?
To learn how to set up and solve this sort of exercise, try here. Once you have studied the lesson and worked through the examples, please attempt this exercise. If you get stuck, please reply showing all of your efforts, so we can see where things are going sideways. You'll start with:

. . .eastward flight:
. . . . .distance: d = 3000
. . . . .rate: r = 600
. . . . .time: t = d/r = 3000/600 = ...?

. . .westward flight:
. . . . .distance: d = 3000
. . . . .rate: r = ...?
. . . . .time: t = ...?

The average rate (distance per time) for the two flights together is of course the total distance (there and back) divided by the total time (for both flights). What value do you get?

Thank you!

#### mathprogram

##### New member
"Let's say a jet leaves Los Angeles and flies straight across the country to New York City. Thanks to the jet stream, the jet enjoys a brisk tailwind and averages 600mph for the 3000 mile distance. On the return flight, back to L.A., the jet encounters the same jet stream, this time of course as a headwind. Therefore, the jet averages only 4000mph for the 3000 mile return trip.

What is the average speed of the plane for the entire round-trip flight or journey"?

3000/600= 5 hours

3000/400= 7.5 hours

So the total time of the trip is ...?

Average speed= Distance/time= ...? This leads to your answer

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