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

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.

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

In how many ways 4 different white balls and 6 different black balls be arranged in a row that no two white balls are together ?

In how many ways 4 different white balls and 6 different black balls be arranged in a row that no two white balls are 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.

Find the number of ways by which 4 green, 3 red and 2 white balls can be arranged in a row such that no two balls of the same colour are together. All balls of the same colour are identical.

The number of ways in which 4 different red balls and 8 similar green balls can be arranged in a row so that at most 3 red balls are together is equal to

The number of ways in which 4 different red balls and 8 similar green balls can be arranged in a row so that at most 3 red balls are together is equal to