Number of ways of selecting one or more things out of n dissimilar things are

Number of ways of selecting r consecutive things out of n things

The number of ways of selecting ' n ' things out of '3n ' things of which 'n ' are of one kind and alike and 'n ' are of second kind and alike and the rest unlike is :

Find the number of selections of one or more things from the group of p identical things of one type, q identical things of another type, r identical things of the third type and n different things.

If the difference of the number of arrangements of three things from a certain number of dissimilar things and the number of selection of the same number of things from them exceeds 100, then the least number of dissimilar things is a. 8 b. 6 c. 5 d. 7

If the number of ways of selecting n cards out of unlimited number of cards bearing the number 0,9,3, so that they cannot be used to write the number 903 is 96, then n is equal to

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

If the number of ways of selecting r balls with replcement out of n balls numbered 1,2,3……,100 such that the largest number selected is 10 is 271, then r= (A) 4 (B) 5 (C) 3 (D) none of these

If the number of ways of selecting 3 numbers out of 1, 2, 3, ……., 2n+1 such that they are in arithmetic progression is 441, then the sum of the divisors of n is equal to

Find the number of ways of selecting 10 balls out of an unlimited number of identical white, red, and blue balls.

No. of combinations by selecting one or more than one object out of n objects is: