Log2 7 * log7 4 = log2 7 * (log2 4 / log2 7) = (log2 7 * log2 4)/log2 7 = log2 4=2
50% - мальчиков
50% - девочек
50%*28% + 50%*16% = 14% + 8% = <u><em>22% - занимаются спортом</em></u>
X>0
<span>¼log₂x+½log₂x+log₂x=7 (•4) </span>
<span>log₂x+2log₂x+4log₂x=28 </span>
<span>7log₂x=28 </span>
<span>log₂x=4 </span>
x = 16
не уверена.