In simultaneous toss of 4 coins, what is the probability of getting two head and two tail:

$\frac{3}{8}$

By tossing four coins, the possible outcomes are (H,H,H,H), (T,H,H,H), (H,T,H,H), (H,H,T,H), (H,H,H,T), (T,T,H,H), (T,H,T,H), (T,H,H,T), (H,T,T,H), (H,T,H,T), (H,H,T,T), (T,T,T,H), (T,T,H,T), (T,H,T,T), (H,T,T,T), (T,T,T,T) where H represents occurrence of head while tossing a coin and T represents occurrence of tail while tossing a coin.
Therefore, Total number of possible outcomes = 16
Here, the favourable event is getting two heads and two tails on tossing four coins.
Clearly, the favourable outcomes after tossing four coins are (T,T,H,H), (T,H,T,H), (T,H,H,T), (H,T,T,H), (H,T,H,T) and (H,H,T,T).
Therefore, Number of favourable outcomes = 6
Probability of obtaining two heads and two tails =$\frac{6}{16} =\frac{3}{8}$