1 .(3/4+1/6)/3=11/12*1/3=11/36
2. (5/6+-1/2):9=1/3*1/9=1/27
3. 11/36+1/27=37/108
1 3/4-5/12=4/12=1/3
2. 3-1/16:1/8=3-1/16*8/1=3-8/16=3-1/2=2.1/2
3. 1/3*2.1/2=1/3*5/2=5/6
2 5/6 - 5х = 1 1/3
2 5/6 - 1 1/3 = 5х
5х = 17/6 - 4/3
5х = (17 - 8)/6
5х = 9/6
х = 3/10
1) Р(А)=0,2*0,1(1-0,5)+(1-0,2)*0,1*0,5+0,2*(1-0,1)*0,5=0,016+0,04+0,09=0,146 (14,6%)
2) Р(/В)=0,8*0,9*0,5=0,36
Р(В)=1-Р(/В)=1-0,36=0,64 (64%)
Вот решение))))
20+20+10=50