Two symmetric dice flipped with each dice having two sides painted red, two painted black, one painted yellow and the other painted white. What is the probability that both land on the same colour?

There are n socks in a drawer, of which 3 socks are red. If 2 of the socks are chosen randomly and the probability that both selected socks are red is $${1 \over 2}$$, then what is the value of n ?

Two cards are chosen at random from a deck of 52 playing cards. What is the probability that both of them have the same value ?

In eight throws of a die, 5 or 6 is considered a success. The mean and standard deviation of total number of successes is respectively given by