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    I'm doing some work on direct and inverse proportion and I stumbled on this question which I don't understand. How do you answer it? many thanks

    The variable P is inversely proportional to Q^2 i.e. P=k/Q^2

    Q is increased by 40%.

    What is the percentage change in P in percentage terms?
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    (Original post by choondy1)
    I'm doing some work on direct and inverse proportion and I stumbled on this question which I don't understand. How do you answer it? many thanks

    The variable P is inversely proportional to Q^2 i.e. P=k/Q^2

    Q is increased by 40%.

    What is the percentage change in P in percentage terms?
    If Q increases by 40%, what does Q^2 increase by? And why am I asking you this?
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    (Original post by SeanFM)
    If Q increases by 40%, what does Q^2 increase by? And why am I asking you this?
    I assume that you multiply Q by 1.4 so you'll end up with (1.4Q)^2, which is 1.96Q^2. That's as far as I got so far.
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    (Original post by choondy1)
    I assume that you multiply Q by 1.4 so you'll end up with (1.4Q)^2, which is 1.96Q^2. That's as far as I got so far.
    Well done, that is right So in terms of P from before, what is k/(1.96)Q^2?
 
 
 
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