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Math Help - Ratios

  1. #1
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    Ratios

    How do I convert 65 miles per hour to feet per second?
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    \frac{65 \, miles}{hour} \cdot \frac{5280 \, ft}{mile} \cdot \frac{1 \, hour}{3600 \, sec} =

    or, you can remember the fact that 60 mph = 88 ft/sec and use a ratio ...

    \frac{x}{65} = \frac{88}{60}
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  3. #3
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    Thanks alot! I should have put that I already knew those steps. I'm looking at the steps and have no clue how to do the next part. That's what's confusing me.
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    Anyone?

    Also I'm trying to convert 45 seconds to 30 minutes as a fraction in simplest form. Would I make 30 minutes into seconds like 30 minutes equals 1800 seconds, so the ration to change to a fraction would be 45/1800?
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    Anyone?
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    Quote Originally Posted by ladyk View Post
    Anyone?

    Also I'm trying to convert 45 seconds to 30 minutes as a fraction in simplest form. Would I make 30 minutes into seconds like 30 minutes equals 1800 seconds, so the ration to change to a fraction would be 45/1800?
    1 minute has 60 seconds
    so 30 minutes has 30 \times 60 = 1800 seconds.

    So the ratio is - 45:1800

    Both are divisible by 45 hence divide both sides by 45 to get the ratio in it simplest form.

    EDIT: Create new thread for new question because some people might not check thread thinking it is answered. So, rather than waiting, create a new thread (It's also a forum rule #15: Rules).
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  7. #7
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    I will do that Air. Thanks alot. And thanks for telling me a forum rule, otherwise I would have missed it.

    Air, would I do the same thing for the first question? I'm still stuck on that one.
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  8. #8
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    Quote Originally Posted by ladyk View Post
    I will do that Air. Thanks alot. And thanks for telling me a forum rule, otherwise I would have missed it.

    Air, would I do the same thing for the first question? I'm still stuck on that one.
    Quote Originally Posted by skeeter View Post
    \frac{65 \, miles}{hour} \cdot \frac{5280 \, ft}{mile} \cdot \frac{1 \, hour}{3600 \, sec} =

    or, you can remember the fact that 60 mph = 88 ft/sec and use a ratio ...

    \frac{x}{65} = \frac{88}{60}
    Follow skeeter's advice. Here's it described further:

    1 mph =  \frac{88}{60} ft/sec

    so 65 mph will be:

    1 \times 65 mph  =  \frac{88}{60} \times 65 ft/second.
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  9. #9
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    My question is this. I want to understand how I would have gotten 88/60. Did I divide something? And did that something have to do with 1 mile equaling 5280 feet, and 3600 in one hour?
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    Quote Originally Posted by ladyk View Post
    My question is this. I want to understand how I would have gotten 88/60. Did I divide something? And did that something have to do with 1 mile equaling 5280 feet, and 3600 in one hour?
    1 mile equals 5280 feet
    1 hour equals 3600 seconds

    So when we have 1 mile per hour, This is the same as:

    5280 feet per 3600 seconds

    But as we want ft/sec, so for 1 second, we divide the value by 3600 so we get:

    \frac{5280}{3600} ft/sec which simplifies to \frac{88}{60} ft/sec

    So, by this:

    1 mph = \frac{88}{60} ft/sec

    Last edited by Simplicity; August 9th 2008 at 08:14 AM. Reason: Typo Correction
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  11. #11
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    Why do you have 5250 instead of 5280?
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  12. #12
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    Quote Originally Posted by ladyk View Post
    Why do you have 5250 instead of 5280?

    Oops, it's a typo. I've corrected it.

    It is 5280, not 5250.
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  13. #13
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    Oh,lol I'm sorry to be asking so many questions, but I want to know exactly what I'm doing and the steps that I am taking. Is 88/60 5280/3600 simplified?
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  14. #14
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    Quote Originally Posted by ladyk View Post
    Oh,lol I'm sorry to be asking so many questions, but I want to know exactly what I'm doing and the steps that I am taking. Is 88/60 5280/3600 simplified?
    Yes, divide the numerator and the denominator of this fraction \left(\frac{5280}{3600}\right) by 60.
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  15. #15
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    Sorry, another question. Why by 60?
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