There are 5 choices for the first letter, 4 choices for the second letter, 3 choices for the third letter, 2 choices for the fourth letter, and 1 choice for the fifth letter. Therefore, the total number of 5-letter combinations that can be made using the letters a, b, c, d, and e is 5 x 4 x 3 x 2 x 1 = 120. Some examples of these combinations include abced, acbde, and eadbc.
10
6
6! = 6*5*4*3*2*1 = 720
There are 5C3 = 10 combinations.
You can make 5 combinations of 1 number, 10 combinations of 2 numbers, 10 combinations of 3 numbers, 5 combinations of 4 numbers, and 1 combinations of 5 number. 31 in all.
20
10
6
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.
Noon Onon nono nnoo oonn So thats 5.
20
9!/5! or 3024
How many four digit combinations can be made from the number nine? Example, 1+1+2+5=9.
6! = 6*5*4*3*2*1 = 720
21
fifty * * * * * What sort of rubbish answer is that? There are 10C5 = 10*9*8*7*6/(5*4*3*2*1) = 252 combinations.
If no digit can be repeated then there are 5 combinations, abcd, abce, abde, acde and bcde. If you regard abdc as different from abcd then each of the 5 basic sets could be arranged 24 ways and the total would be 120 combinations.