SOLUTION: Z W Y X The sequence above may be changed in either of two ways. Either two adjacent letters may be interchanged or the entire sequence may be reversed. What is the least number o

Question 338550: Z W Y X
The sequence above may be changed in either of two ways. Either two adjacent letters may be interchanged or the entire sequence may be reversed. What is the least number of such changes needed to put the letters into alphabetical order left to right?
A. 2 B. 3 C. 4 D. 5 E. 6
Answer by Edwin McCravy(20056) (Show Source): You can put this solution on YOUR website!


ZWYX

We cannot do it in only two changes because these

WZYX, ZYWX, ZWXY, XYWZ 

are the only possible results after one change, and the 
final result of WXYZ cannot be obtained from any of these 
in only one additional change.

However we can change ZYWX to ZYXW to WXYZ,

or

we can change XYWZ to XWYZ to WXYZ.

So the least number of changes possible is 3.

Edwin

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