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Mathematics 19 Online
OpenStudy (anonymous):

Two jets leave an air base at the same time and travel in opposite directions. One jet travels 66 mi/h faster than the other. If the two jets are 7692 mi apart after 6 hours, what is the rate of each jet?

OpenStudy (inkyvoyd):

okay... so any ideas?

OpenStudy (anonymous):

Well, I know we need to make a distance, rate, time table. We also need to find out what x and y will be...

OpenStudy (inkyvoyd):

mind telling me what the title of your unit is? there's a few ways to do this problem and I want to know which way you are supposed to do

OpenStudy (anonymous):

The topic name is: Solving a distance, rate, time problem using a system of linear equations.

OpenStudy (inkyvoyd):

okay goodie. So, waht's the relationship between distance and rate?

OpenStudy (anonymous):

If you multiply time and rate you get a distance.

OpenStudy (inkyvoyd):

Yup. So in the case of our jets, what exactly is the rate? first jet? second jet? both jets?

OpenStudy (inkyvoyd):

what do you think our variables should be?

OpenStudy (anonymous):

Our variables should stand for the jets rates, I think...

OpenStudy (anonymous):

Like x for the faster jet and y for the slower jet...

OpenStudy (anonymous):

Hello?

OpenStudy (inkyvoyd):

omg sorry

OpenStudy (inkyvoyd):

and yes, that's correct. so what does x+y stand for?

OpenStudy (anonymous):

It's okay. :)

OpenStudy (anonymous):

Not sure..

OpenStudy (inkyvoyd):

x+y is the total rate right? jets are moving in different directions so the distance apart for time t is (x+y)t no?

OpenStudy (anonymous):

I guess, I don't know I feel confused...

OpenStudy (anonymous):

What do I write down for what x and y actually stand for?

OpenStudy (inkyvoyd):

What you said. Like x for the faster jet and y for the slower jet... faster jet's RATE.

OpenStudy (inkyvoyd):

they asked us to do rate, so let's set our variables as rate to make it easy right?

OpenStudy (anonymous):

And if I were to make a table for this information, then what do I write under the rate column for each jet?

OpenStudy (inkyvoyd):

What are the columns of your table?

OpenStudy (anonymous):

The columns are rate, time, and distance. And then the rows are faster jet and slower jet.

OpenStudy (inkyvoyd):

Okay. So, we just said rate of jets are x for faster and y for slower right?

OpenStudy (anonymous):

Right.

OpenStudy (inkyvoyd):

Ok, what about time?

OpenStudy (anonymous):

Time is 6 hours for both.

OpenStudy (inkyvoyd):

And distance?

OpenStudy (anonymous):

Well, I guess for the faster jet it would be 6x and for the slower jet it would be 6y...

OpenStudy (inkyvoyd):

but that completes the tables. Let's move on to the equations...

OpenStudy (inkyvoyd):

So, we'll need 2 equations because we have 2 variables... any ideas?

OpenStudy (anonymous):

Not really. I would say 6x = 7692 and 6y = 7692 but I think these are wrong.

OpenStudy (anonymous):

Does it have something to do with the 66 mi/h?

OpenStudy (inkyvoyd):

oh... 7692 doesn't actually work LOL

OpenStudy (inkyvoyd):

so yes you were right regarding 6x and 6y :)

OpenStudy (inkyvoyd):

and, what do we know about the 66mi/h?

OpenStudy (anonymous):

That it is a rate? >_<

OpenStudy (inkyvoyd):

is it? what did the problem say 66 mi/h was?

OpenStudy (anonymous):

It is how much faster one of the jets is going compared to the slower one.

OpenStudy (inkyvoyd):

and how can we write that in math?

OpenStudy (anonymous):

I'm guessing we need to multiply here??

OpenStudy (inkyvoyd):

Well, I was really just asking you to trasnlate your statement from an english sentence to a mathematical statement... in other words an equation expressing the relationships between how much faster the jets are going...

OpenStudy (anonymous):

66x = y ??

OpenStudy (inkyvoyd):

and you said x and y are the rates of the jets right? you're saying here, the faster jet's speed multiplied by 66 is equal to the slower jet?

OpenStudy (anonymous):

I guess. :/

OpenStudy (inkyvoyd):

Well, if it seems weird, fix it :P

OpenStudy (anonymous):

That's incorrect, isn't it?

OpenStudy (inkyvoyd):

What was the original statement again?

OpenStudy (anonymous):

I don't know what to fix it to.

OpenStudy (inkyvoyd):

No worries, let's start over from the statement. What's the sentence we're trying to translate?

OpenStudy (anonymous):

The rate of 66 mi/h is how much faster one of the jets is going compared to the slower one.

OpenStudy (inkyvoyd):

How about just, One jet's rate is 66 mi/h more than another jet's rate?

OpenStudy (inkyvoyd):

Wanna try translating that one to math? :P

OpenStudy (anonymous):

Is it supposed to be an equation?

OpenStudy (inkyvoyd):

We're turning this word problem into a math problem... we need 2 equations no? and we're using the information from the problem to get both?

OpenStudy (anonymous):

Wait. I figured it out.

OpenStudy (anonymous):

x + 66 = y ???

OpenStudy (inkyvoyd):

the faster jet's speed plus 66 mi/h equals the slower jet's speed?

OpenStudy (anonymous):

** y + 66 = x

OpenStudy (inkyvoyd):

yup!. ok, one down, one more.

OpenStudy (inkyvoyd):

this equation... will probably use the rest of the information we have, right?

OpenStudy (anonymous):

Right.

OpenStudy (inkyvoyd):

any ideas?

OpenStudy (anonymous):

Well, as you just said, it's going to have something to do with the 7692 miles.

OpenStudy (inkyvoyd):

ok what is the significance of the 7692 miles?

OpenStudy (anonymous):

It is how far the two jets are after 6 hours.

OpenStudy (inkyvoyd):

Can you translate that statement?

OpenStudy (anonymous):

7692 = 6x + 6y ??

OpenStudy (inkyvoyd):

aha. yup.

OpenStudy (inkyvoyd):

And how do we solve this?

OpenStudy (anonymous):

We can add the equations after we get y alone on one side?

OpenStudy (anonymous):

Then figure out one of the variables.

OpenStudy (inkyvoyd):

well, that is the slow way :)

OpenStudy (anonymous):

What other way is there?

OpenStudy (anonymous):

OH WAIT

OpenStudy (anonymous):

We can put (y + 66) into the equation for x...

OpenStudy (inkyvoyd):

yes...

OpenStudy (inkyvoyd):

let me know what you get for x and y

OpenStudy (anonymous):

y = 608 x = 674

OpenStudy (inkyvoyd):

That's what I got :)

OpenStudy (anonymous):

Thank you so much for all your help and sorry for being so clueless!

OpenStudy (anonymous):

I just have one question left. :)

OpenStudy (inkyvoyd):

no problem - you weren't very clueless at all; most people wouldn't be able to steer themselves into the solution that easily... I have to head to bed, but I'm sure you'll find someone to help you with for your next problem! best wishes

OpenStudy (anonymous):

Thanks! :)

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