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Math

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If y varies directly as x and y=3 when x=10, find x when y=8? Can you please show me step by step solution for this problem?

  • Math -

    Whenever you have a statement such like yours,
    "If y varies directly as x "
    you can form the equation
    y = kx , where k is a constant

    sub in the given: y=3 , x=10 to find k
    3 = k(10)
    k = 3/10

    so your equation is y = (3/10)x

    then when y = 8

    8 = (3/10)x
    80 = 3x
    x = 80/3

    btw, if it has said" y varies inversely as x" your equation would have been
    y = k(1/x), but you would follow the same steps of subbing in the given data to find k

  • Math -

    Thank you so much that helps a lot!

  • Math -

    welcome

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