1) 20 * 5 : 1 = 100
2)40 * 3 : 1 = 120
3)50 * 6 : 1 = 300
4)30 * 2 : 1 = 60
5) 50* 4 : 1 = 200
6) 40 * 8 = 320
12 ÷ <span>27/8</span> = 12 × <span>8/27</span> = <span>12·8/27</span> = <span>96/27</span> = 3 <span>5/9</span><span> ≈ 3.5555555555555554</span>
Всего-x
0,5x+(0,5x:2)*2/3+10+5=x
0,5x+1/6x-x=-15
3/6x+1/6x-x=-15
-1/3x=-15:(-1/3)
x=45