Suppose i have an urn with 9 balls: 4 green, 3 yellow and 2 white ones. i draw a ball from the urn repeatedly with replacement.

(a) suppose i draw n times. let xn be the number of times i saw a green ball followed by a yellow ball. calculate the expectation e[xn].
(b) let y be the number of times i drew a green ball before the first white draw. calculate e[y ]. can you give an intuitive explanation for your answer?

the answer is 28

step-by-step explanation:

i think the answer is b.

step-by-step explanation:

not 100% sure though.

a ≈ 172.05

step-by-step explanation:

the pictures.

option (a)

step-by-step explanation:

step 1:   take 2 number whose product equal to 25..

and sum of those two number are -10

step: 2 for example here if we take 5,5 are the number,,

5*5=25

and

5+5=10

but we need -10

so if we take   -5,-5

so -5*-5=25

and -5+(-5)=-10

s0

come the equation

replace -10x by these number

like -5x -5x+25

take common

x(x-5)-5(x-5)=0

(x-5)(x-5)=0