Answer:
At every pick the probability may vary depending upon your guess is right or wrong.
Step-by-step explanation:
First pick:
Equal probability for both red and blue = 1/2
Second pick:
case 1: If first pick was red.
then predict blue because the probability of blue exceeds the probability of red.
P(b) = 2/3
P(r) = 1/3
case 2: if first pick was blue.
then predict red because the probability of red exceeds the probability of blue.
P(r) = 2/3
P(b) = 1/3
Third pick:
case 1: R,B
then predict either red or blue due to equal probabilities.
note: Similar case for B,R.
case 2: RR
then obviously you will predict blue because P(b)=1 and vice versa for the case if the first two draws were BB.
Fourth Pick:
Fourth pick would be obvious because you are left with only remaining colored ball for which the probability must be 1.