For question number one,
I guess:
If X~U(a,b):E(X)=(a+b)/2 ,V(X)=〖(b-a)〗^2/12
We have:E(X)=(a+b)/2=10 ,V(X)=〖(b-a)〗^2/12=〖(2.5)〗^2
By two define and two passive:a=5.67 ,b=14.33
So: X~U(5.67,14.33)
Area space=π〖(X/2)〗^2
→E(π(X/2)^2 )=π/4 E(X^2 )=π/4[V(X)+〖E(X)〗^2]
=π/4...