There can be only one combination, and that is abcde.
In a combination the order of the elements does not matter, so dabec is the same as abcde.
6
10
5. One each with one of the 5 letters left out: abcd, abce, abde, acde and bcde.
6! = 6*5*4*3*2*1 = 720
There are 5C3 = 10 combinations.
20
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.
6
10
20
5. One each with one of the 5 letters left out: abcd, abce, abde, acde and bcde.
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
fifty * * * * * What sort of rubbish answer is that? There are 10C5 = 10*9*8*7*6/(5*4*3*2*1) = 252 combinations.
21