`3` red and `4` white balls of different sizes are arranged in a row at random. The probability that no two balls of the same colour are together is

5 red balls and 4 black balls of different sizes are arranged in a row at random. The probability that no two balls of the same colour come together is

The number of ways in which 5 red balls , 4 black balls of different sizes can be arranged in a row so that no two balls of the same colour come together is

Find the number of ways in which 5 red balls, 4 black balls of different sizes can be arranged in a row so that no two balls of the same colour come together.

Find the number of ways in which 5 red balls, 4 black balls of different sizes can be arranged in a row so that the balls of the same colour come together.

The number of ways in which 20 different white balls and 19 different black balls be arranged in a row,so that no two balls of the same colour come together is

A bag contains 8 red and 7 black balls. Two balls are drawn at random. The probability that both the balls are of the same colour is :

A bag contains 8 red and 7 black balls. Two balls are drawn at random. The probability that both the balls are of the same colour is :

A bag contains 8 red and 7 black balls. Two balls are drawn at random. The probability that both the balls are of the same colour is :