а)
-2*15=-30
-2*-5.5=11
-2*0.8=-1.6
б)
0.5*-48=-24
0.5*-1.6=-0.8
0.5*2.4=1.2
0.5*-0.1=-0.05
S=n1+n2+n3=900
n1=900×2/5=360
n2+1/6(n1)=n1 --> n2=n1-1/6(n1)=5/6(n1)=300
n3=S-(n1+n2)=900-(360+300)=900-360-300=240