C(0) = 9/ 12
c( 1)= 3/ 12 * 9/ 1 1
c(2)= 3/ 12 * 2/ 1 1 * 9/ 10
c(3)= 3/ 12 * 2/ 1 1 * 1/ 10
e(∮)= 1 * c( 1)+2 * c(2)+3 * c(3)
= 0.3
Probability c (∮) = 4c ∮ * 0.4 (4-∮) * 0.6 ∮.
C(0) = 4C0 * 0.4^4
c( 1)= 4c 1 * 0.4)^3 *(0.6)
C(2) = 4C2 * 0.4^2 * (0.6)^2
C(3) = 4C3 * 0.4 * (0.6)^3
C(4) = 4C4 * 0.6^4
e(∮)= 1 * c( 1)+2 * c(2)+3 * c(3)+4 * c(4)
= 2.4