Question 1143184
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<pre>
Let x = the number of girls in the class last year.


Then from the condition, you have this equation


    {{{(15-x)/x}}} = 0.15.


Solve it for x


    15 - x = 0.15x


    15 = 0.15x + x

    15 = 1.15x

    x  = {{{15/1.15}}} = 13.043.


Round to the closest integer  x= 13.    <U>ANSWER</U>
</pre>


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Usually, the problems of this kind are formulated to get an integer number as the answer without rounding . . . 


Or, if rounding is necessary, then the condition says about it directly and explicitly.