Two red counters, three green counters and four blue counters are placed in a row in random order. The probability that no two blue counters are adjacent is

Let $$A$$ and $$B$$ be two independent events such that the odds in favour of $$A$$ and $$B$$ are $$1: 1$$ and $$3: 2$$, respectively. Then, the probability that only one of the two occurs is

Two dices are rolled. If both dices have six faces numbered $$1,2,3,5,7$$ and $$11$$ then the probability that the sum of the number on the top faces is less than or equal to 8 is

A bag contains 50 tickets numbered $$1,2,3, ..., 50$$ of which five are drawn at random and arranged in ascending order of magnitude $$\left(x_1 < x_2 < x_3 < x_4< x_5\right)$$, then the probability that $x_3=30$ is