Permutations and Combinations
The number of integers greater than 6,000 that can be formed, using the digits 3,5,6,7and8, without repetition, is :
Number of ways in which Rs. 18 can be distributed amongst four persons such that nobody receives less than Rs. 3 is a. 42 b. 24 c. 4! d. none of these
How many 3-digit numbers can be formed from the digits 1,2,3,4 and 5 assuming that.
Number of ways in which three numbers in A.P. can be selected from 1,2,3,…,n is a. (2n−1)2 if n is even b. n4n−2 if n is even c. 4(n−1)2 if n is odd d. none of these
The number of different ways in which five "alike dashes" and "eight alike" dots can be arranged using only seven of these "dashes" and "dots" is a. 350 b. 120 c. 1287 d. none of these
A is a set containing n elements. A subset P1 is chosen and A is reconstructed by replacing the elements of P1. The same process is repeated for subsets P1,P2,….,Pm with m>1. The number of ways of choosing P1,P2,….,Pm so that P1∪P2∪….∪Pm=A is (a)(2m−1)mn (b)(2n−1)m (c)(m+n)Cm (d) none of these
The value of expression .47C4+j=1∑5.52−jC3 is equal to a..47C5 b. .52C5 c. .52C4 d. none of these