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Math Help - Finding percentage

  1. #1
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    Finding percentage

    Light intensity l relative to depth d (in feet) for one of the clearest bodies of water in the world, the Sargasso Sea in the West Indies, can be approximated by l = l0e^-0.00942d where lo is the intensity of light at the surface. What percentage of the surface light will reach a depth of A) 50 feet B) 100 feet?
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  2. #2
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    Just do the arithmetic! Putting d= 50 and 100 in that formula gives the light intensity as a fraction times the surface light. The "percentage" is just that fraction changed to a percent.
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  3. #3
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    Quote Originally Posted by HallsofIvy View Post
    Just do the arithmetic! Putting d= 50 and 100 in that formula gives the light intensity as a fraction times the surface light. The "percentage" is just that fraction changed to a percent.
    what would that leave l and l0?
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  4. #4
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by dc52789 View Post
    what would that leave l and l0?
    i don't get your question
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  5. #5
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    Quote Originally Posted by Jhevon View Post
    i don't get your question
    I'm trying to figure out what the l and lo is?
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by dc52789 View Post
    I'm trying to figure out what the l and lo is?
    in that case, HallsofIvy answered your question. just plug in the values. what do you get? you will get that the intensity is some decimal times I_0. this decimal will tell you the percentage

    you are not required to find the values of I and I_0 specifically
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  7. #7
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    Quote Originally Posted by Jhevon View Post
    in that case, HallsofIvy answered your question. just plug in the values. what do you get? you will get that the intensity is some decimal times I_0. this decimal will tell you the percentage

    you are not required to find the values of I and I_0 specifically
    So...do I just do e^(-0.00942x50) and e^(-0.00942x100)?
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  8. #8
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by dc52789 View Post
    So...do I just do e^(-0.00942x50) and e^(-0.00942x100)?
    yes. and in each case, say what percentage of the surface intensity you have
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  9. #9
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    Quote Originally Posted by Jhevon View Post
    yes. and in each case, say what percentage of the surface intensity you have
    I have A) 0.6244 B) 0.3898
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  10. #10
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    Convert to a percentage

    To convert decimal to percent just multiply by 100.
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  11. #11
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    Quote Originally Posted by Here to Help View Post
    To convert decimal to percent just multiply by 100.
    that would be 62.44% and 38.98%
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