Question 1148874
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<pre>

Let x be the number of boys.  Then the number of girls is 805-x.


    {{{(805-x)/x}}} = {{{3/4}}}


    4*(805-x) = 3x

    4*805 -4x = 3x

    4*805 = 3x + 4x

    4*805  = 7x

    x = {{{(4*805)/7}}} = 4*115 = 460.


<U>ANSWER</U>.  460 boys.


<U>CHECK</U>.   {{{805-460)/460}}} = {{{345/460}}} = {{{(3*115)/(4*115)}}} = {{{3/4}}}.    ! Correct !
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Solved.