Seven white and 3 black balls are placed in a row. What is the probability if two black balls do not occur together ?

Seven white balls and three black balls are randomly placed in a row. What is the probability that no two black balls are placed adjecently ?

Seven white balls and three black balls are randomly placed in a row. IF the parabability that no two black balls are placed adjacently, equals (7/a), then the value of "a" is

The number of ways of arranging m white and n black balls in a row (mgtn) so that no two black are placed together, is

In how many ways can 21 identical white balls and 19 identical black balls be arranged in a row so that no 2 black 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 ?

An urn contains 5 white and 3 black balls and 4 balls are drawn at random.The probability of getting white and black balls equal in number is-

A bag contains 4 red and 3 black balls.If one ball is drawn at random,then what is the probability of drawing a black ball?