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Math Help - Percentage Of Population Increase

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    Member Rimas's Avatar
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    Percentage Of Population Increase

    In 1988 the population f Abra increased by 20% while the population of Cadabra decreased by 10% after which thw two populations were equal. What % of the original population of Cadabra was the orginal poplation of Abra?
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    Quote Originally Posted by Rimas View Post
    In 1988 the population f Abra increased by 20% while the population of Cadabra decreased by 10% after which thw two populations were equal. What % of the original population of Cadabra was the orginal poplation of Abra?
    population of Abra P.A. = x + 20%x = x(1+20%)
    population of Cadabra P.C.= y(1- 10%)

    then they becom equal so
    x= y (1- 10%)/(1+20%)=9y/12
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    Quote Originally Posted by Rimas View Post
    In 1988 the population f Abra increased by 20% while the population of Cadabra decreased by 10% after which thw two populations were equal. What % of the original population of Cadabra was the orginal poplation of Abra?
    Hello,

    let A be the population of Abra and
    let C be the population of Cadabra.

    Then you can set up the equation:

    120\% A= 90\% C \Longrightarrow \frac{A}{C}=\frac{90\%}{120\%}=\frac{3}{4}

    That means the population of A was 3/4 = 75% of C.

    EB
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