Question 33697
<pre><font size = 4><b>how many different ways can you write the following using 
probability, permutations or combinations
a<sup>4</sup>b<sup>2</sup>c<sup>5</sup>d
There are four factors a<sup>4</sup>, b<sup>2</sup>, c<sup>5</sup>, and d.  
There are 4 choices of factors to go first. 

Then for each of those 4 possible ways to choose the 
first factor, there are 3 factors remaining to choose 
for the 2nd factor. That's 4×3 or 12 ways to choose 
the first two factors.

Then for each of those 4×3 or 12 possible ways to choose 
the first two factors, there are 2 factors remaining to 
choose for the 3rd factor. That's 4×3×2 or 24 ways to choose 
the first three factors.

Then for each of those 4×3×2 or 24 possible ways to choose 
the first two factors, there is only 1 factor remaining to 
choose for the 4th factor. That's 4×3×2×1, or still 24 ways 
to choose the first four factors.

It can also be called 4! or "the number of permutations of 4
things taken 4 at a time.

These are

 1. a<sup>4</sup>b<sup>2</sup>c<sup>5</sup>d 
 2. a<sup>4</sup>b<sup>2</sup>dc<sup>5</sup> 
 3. a<sup>4</sup>c<sup>5</sup>b<sup>2</sup>d
 4. a<sup>4</sup>c<sup>5</sup>db<sup>2</sup>            
 5. a<sup>4</sup>db<sup>2</sup>c<sup>5</sup>                         
 6. a<sup>4</sup>dc<sup>5</sup>b<sup>2</sup>                         
 7. b<sup>2</sup>a<sup>4</sup>c<sup>5</sup>d             
 8. b<sup>2</sup>a<sup>4</sup>dc<sup>5</sup>             
 9. b<sup>2</sup>c<sup>5</sup>a<sup>4</sup>d
10. b<sup>2</sup>c<sup>5</sup>da<sup>4</sup>
11. b<sup>2</sup>da<sup>4</sup>c<sup>5</sup>
12. b<sup>2</sup>dc<sup>5</sup>a<sup>4</sup>
13. c<sup>5</sup>a<sup>4</sup>b<sup>2</sup>d
14. c<sup>5</sup>a<sup>4</sup>db<sup>2</sup>
15. c<sup>5</sup>b<sup>2</sup>a<sup>4</sup>d
16. c<sup>5</sup>b<sup>2</sup>da<sup>4</sup>
17. c<sup>5</sup>da<sup>4</sup>b<sup>2</sup>
18. c<sup>5</sup>db<sup>2</sup>a<sup>4</sup>
19. da<sup>4</sup>b<sup>2</sup>c<sup>5</sup>
20. da<sup>4</sup>c<sup>5</sup>b<sup>2</sup>
21. db<sup>2</sup>a<sup>4</sup>c<sup>5</sup>
22. db<sup>2</sup>c<sup>5</sup>a<sup>4</sup>
23. dc<sup>5</sup>a<sup>4</sup>b<sup>2</sup>
24. dc<sup>5</sup>b<sup>2</sup>a<sup>4</sup>

Edwin 
AnlytcPhil@aol.com</pre>