1. Ankita and Nagma re two friends. They were both born in 1990. What is the probability that they have (1) same birth day

(2)different birth days?

Hey,

here's the solution

Let Ankita be A, let Nagma be B, let the year be a normal year (365 days)

Possible birthdays :  (1-1, 1-1) , (1-1, 1-2),...... (1-1, 31-12), (1-2, 1-1),.. .........................., (31-12, 31-12)

so the above total adds up to 365 * 365 = 133225

the no. of outcome when the birthday will be same is 365

so P (having same birthday )  = 365/ 133225  = 1/365 ans.(i)

and P (having different birthday) = (133225-365) / 133225 = 364/365 ans (ii)

Hope this helps!