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Math Help - A variation problem

  1. #1
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    A variation problem

    The current flowing in an electrical circuit at a constant potential varies inversely as the resistance of the circuit. If the current is 25 amperes when the resistance is 4 ohms, what is the current when the resistance is 5 ohms?

    What is the answer?
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  2. #2
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    Is the answer 20?
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  3. #3
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    Hello,

    The current I variates inversely as the resistance R.

    This means that there exists k such as :

    I=k/R -> k=RI

    For I=25, R=4.

    And you want to know I' if R'=5.

    So I'=k/R'=RI/R'=4*25/5=20
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  4. #4
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    Quote Originally Posted by mt_lapin View Post
    Is the answer 20?
    Yep
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