1. ## Word Problem.

Alright, here is the problem-
Flying against the jetstream, a jet travels 3500km in 5 hours. Flying with the jetstream, the same jet travels 6580km in 7 hours.

What is the speed of the jet in still air, and what is the speed of the jetstream?

So going against the jetstream, the jet gets about 700km/h.
And going with the jetstream, the jet gets 940km/h.

So, how do I find the speed of the jet if there is NO jetstream, and then the speed of the jetstream?

Thanks!

I'm sure this is way less complicated than I am making it seem to be.

2. Ok, you have already figured out the speed of the jet going both directions and I will trust that you have done those correctly.

With the jetstream = 940 km/h

Against the jetstream = 700 km/h

Let's call the speed of the jet $\displaystyle x$ and the speed of the jetstream $\displaystyle y$.

When traveling with the jetstream:

$\displaystyle x+y=940$

When traveling against the jetstream:

$\displaystyle x-y=700$

We know that the absolute speed of the jet is the same in both cases, so let's isolate $\displaystyle x$ in the first equation:

$\displaystyle x = 940 - y$

Now sub that into the second equation:

$\displaystyle (940-y)-y=700$

Solve for y, then sub that value into either of the first two equations to solve for x.

3. Okay, so I figure the jetstream to equal 120km/h and the speed of the Jet at 820km/h.

Am I right? (just making sure)

4. Yes you are right, assuming that the velocities you calculated are correct.