srcc25anu wrote:A and B play a game. A and B alternately roll a pair of dice (A starts the game). The first person to throw a score more than what the other has scored in the previous throw is said to have won the game. What is the probability that B wins the game in the second throw?
1. 575/1296
2. 1/2
3. 175/1296
4. 23/36
Probability that B wins the game in the 2nd throw (first throw for B, however 2nd overall for the game as A has the first throw) =
P(A=2)P(B>2)+P(A=3)P(B>3)+P(A=4)P(B>4)+P(A=5)P(B>5)+P(A=6)P(B>6)+P(A=7)P(B>7)+P(A=8)P(B>8)+P(A=9)P(B>9)+P(A=10)P(B>10)+P(A=11)P(B>11)
=1/36*35/36+2/36*33/36+3/36*30/36+4/36*26/36+5/36*21/36+6/36*15/36+5/36*10/36+4/36*6/36+3/36*3/36+2/36*1/36
= 1/36*36 * (35+66+90+104+105+90+50+24+9+2) = 575/1296.
1
Thanks
Anshu
(Every mistake is a lesson learned )