Question 155603
{{{E(X)=10(0.05)+20(0.65)+30(0.05)+40(0.20)+50(0.05)=0.5+13+1.5+8+2.5=25.5}}}
{{{V(X)=E(X^2)-E(X)^2}}}

{{{E(X^2)=10^2(0.05)+20^2(0.65)+30^2(0.05)+40^2(0.20)+50^2(0.05)}}}=
{{{5+260+45+320+125=755}}}

{{{V(X)=755-(25.5)^2=104.75}}}
Answer: {{{E(X)=25.5}}} and {{{V(X)=104.75}}}