--------------1.-------------
E(x)=1*0.4+3*0.1+5*0.5
=0.4+0.3+2.5
=3.2
D(x)=1^2*0.4+3^2*0.1+5^2*0.5-3.2^2
=0.4+0.9+12.5-10.24
=3.56
--------------2.-------------
(C(3,2)+C(3,1))*2*2
=(3+3)*2*2
=24
--------------1.-------------
E(x)=1*0.4+3*0.1+5*0.5
=0.4+0.3+2.5
=3.2
D(x)=1^2*0.4+3^2*0.1+5^2*0.5-3.2^2
=0.4+0.9+12.5-10.24
=3.56
--------------2.-------------
(C(3,2)+C(3,1))*2*2
=(3+3)*2*2
=24