Recent questions in Discrete Mathematics

1 votes
1 answer
5961
$\sum_{j \in S} 1$ where S = {1, 3, 5, 7}.if we have $\sum_{j = 1}^{n} 1$ then the answer will be n. But what happens if this a set?
1 votes
1 answer
5963
The number of ways in which $2n$ white and $2n$ black balls can be arranged such that no consecutive $n$ white balls are together, is${}^{2n+1}C_2 + {}^{4n}C_{2n}$${}^{2n...
2 votes
0 answers
5965
Find the coefficient of x7 in expansion of (1+3x-2x3)10. How to apply multinomial theorem to solve this types of problems?
1 votes
1 answer
5967
why do we count here empty string also , it has no 1's , so what's the reason for counting this ?
1 votes
1 answer
5969
we have to choose five chocolates,say, C1, C2, C3, C4 and C5. Now for C1 we can choose among three kinds of chocolates. Since the supply of chocolates is infinite, for C2...
0 votes
2 answers
5970
The number of ways in which 6 rings can be worn on the four fingers of one hand is:a. 360b. 4^6c. 6C4d. 6^4
0 votes
3 answers
5971
A class is composed of 2 brothers and 6 other boys. In how many ways can all the boys beseated at a round table so that the two brothers are not seated together?a. 3000b....
67 votes
10 answers
5973
57 votes
17 answers
5974
44 votes
10 answers
5980