Recent questions tagged counting

3 votes
2 answers
61
1 votes
1 answer
66
How many 3 digits number are there which are divisible by 3 and repetition of digits NOT allowed.?
0 votes
1 answer
71
1 votes
1 answer
72
1 votes
0 answers
73
Derangements are permutations $\pi$ of the set $\{1,2, \ldots, n\}$ such that $\pi(i) \neq i.$ Compute the number of derangements on the set $1,2, \ldots, n$.
2 votes
1 answer
74
A gardener wants to buy $3$ neem plants, $5$ rose plants and $1$ banyan plant from a nursery having $7$ neem, $10$ rose and $6$ banyan plants. How many choices does a gar...
1 votes
1 answer
75
0 votes
0 answers
77
Consider a Diffie-Hellman scheme with a common prime q=11 and a primitive root a=2. If user A as public key YA=9 what is as private key XA? If user B has public key YB= 3...