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

If N denotes the number of ways of selecting r objects of out of n distinct objects (rgeqn) with unlimited repetition but with each object included at least once in selection, then N is equal is a. .^(r-1)C_(r-n) b. .^(r-1)C_n c. .^(r-1)C_(n-1) d. none of these

Which of the following is not the number of ways of selecting n objects from 2n objects of which n objects are identical

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 number of ways of selecting pair of black squares in chessboard such that they have exactly one common corner

Find the number of ways of selecting 9 balls from 6 red balls, 5 white balls and 5 blue balls if each selection consists of 3 balls of each colour.

Find the number of ways of selecting 9 balls from 6 red balls, 5 white balls and 5 blue balls if each selection consists of 3 balls of each colour.

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 letters of the word INDEPENDENT. How many words can be formed from these five letters ?

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

There are 4 white, 3 black and 3 red balls in a bag. Find the number of ways of selecting three balls, if at least one black ball is there.