There are 3 consonants from 21 and 2 vowels from 5. That gives 21C3 * 5C2 combinations = 21*20*19/(3*2*1) *5*4/(2*1) = 1330*10 = 13300 combinations in all.
There are 8*7/(2*1) = 28 combinations.
There are 2*2*5 = 20 combinations.
Two make combinations you would take 2x1=2 combinations only
There are 11C2 = 11*10/(2*1) = 55 combinations.
3,124,550 possible combinations
You did not give us the set to work with...
256 iThink * * * * * It depends on combinations of how many. There is 1 combination of 4 letters out of 4, 4 combinations of 3 letters out of 4, 6 combinations of 2 letters out of 4, 4 combinations of 1 letter out of 4. Than makes 15 (= 24-1) in all. Well below the 256 suggested by the previous answer.
2600
12 Combinations.
4
Four outcomes, three combinations.
11
4
There are 9C2 = 9*8/(2*1) = 36 2-digit combinations.
Three combinations: 23, 24 and 34
You would get 4!/2! = 12 combinations.