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I need help on this question don't judge people I'm in 7th grade. Here's the question.

An object is traveling at a steady speed of 9 9/10km/h.  How long will it take the object to travel 5 1/10km?

Oct 18, 2019
edited by Guest  Oct 18, 2019

#1
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An object is traveling at a steady speed of 9 9/10km/h.  How long will it take the object to travel 5 1/10km?

Let's change the fractions to decimal fractions, just to make it easier.

An object is traveling at a steady speed of 9.9 km/h.  How long will it take the object to travel 5.1 km?

The question asks how long, so you know the answer will be in hours.

Figure out how to cancel units, so that the answer will end up in hours.

You know to divide a fraction, you invert the divisor and multiply, so set it up like this

5.1   km                       9..9   km

___ ___    divided by  ____ ___

1     1                           1      hr

so that when you invert the divisor and multiply it becomes

5.1   km                  1     hr              5.1    hr

___ ___    times  ____ ___     =    ____          =   0.515 hr

1     1                  9.9    km            9.9

.

Oct 18, 2019
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You have explained this really well guest.

Melody  Oct 18, 2019
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Thank you, Melody.  Coming from you it's quite a compliment.  I hope that the seed I planted about cancelling units takes root.  Once I grasped that concept, it helped me enormously.  Ron

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Guest Oct 19, 2019
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It did for me too!

It is a concept that is used in Chemistry all the time but it is rarely taught in mathematics.

I do not know why not.

Melody  Oct 19, 2019
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......

.
Oct 18, 2019
edited by Rom  Oct 18, 2019
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THe guest types like CPhill!

CalculatorUser  Oct 18, 2019
edited by CalculatorUser  Oct 18, 2019
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Why did you delete yours Rom?

It was right too!  At least I think it was.

I completmented guest but it was not meant as an insult to you.

I should have said thanks you for your answer as well. Sorry.

Yours was the more usual way to do it...  Some people would have like it better.

Melody  Oct 19, 2019
edited by Melody  Oct 19, 2019
edited by Melody  Oct 19, 2019