400 :20 ×5
400:20=200
200×5=1000
1000м она пройдет за 20 мин
<span> 60 градусов-1/3
<span>120 градусов-2/3
<span>150 градусов-5/18
<span>45 градусов-1/4</span></span></span></span>
<span><span><span><span><span>80 градусов-4/9</span></span></span></span></span>
<span><span><span><span><span><span>12 градусов-1/15</span></span></span></span></span></span>
<span><span><span><span><span><span><span>15 градусов-1/12</span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span>18 градусов-1/10 </span></span></span></span></span></span></span></span>36 градусов-1/5
<span><span><span><span><span><span><span><span><span><span>20 градусов-1/9</span></span></span></span></span></span></span></span></span></span>
3^7/3^2x=1/81
3^(7-2)/3^x=3^(-4)
3^x=3^(-4 -5)
x=-9