Question
A and B take turn in throwing two dice. The first to throw sum 9 being awarded. Show that if A has the first throw, their chances of winning are in the ratio 9:8.
Solution
Let E be the event of getting sum 9 in a throw of two dice.
Now A wins in first throw or third row or 5th throw or................
proability of winning of A = P(E) + 
+ 
probability of winning of B = 
required ratio = 
