Find the number of ways of selecting 3 pairs from 8 distinct objects.

Find the number of ways of selections of 3 balls out of 9 red distinct balls and 6 balck distnct balls if at least one balck ball is here in each selection.

Find the total number of ways of selection of 4 distinct red balls, 2 identical black balls, and 3 identical white balls.

Find the total number of ways of selecting five letters from the word INDEPENDENT.

From a group of persons the number of ways of selecting 5 persons is equal to that of 8 persons.No.of ways of selecting 2 persons is