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 from left to right?
Level of Difficulty E M
Some problems simply involve "playing around" until you get the right answer. If you play around with the given sequence of letters, you will notice that switching the W and Y will produce:
Z Y W X
Then, switching the W and X will give:
Z Y X W
Now all we need is to reverse the entire sequence to get:
W X Y Z
and we have alphabetical order with three (3) changes, or choice B.
For more practice with sequences, go to Skill Set 17: Sequences.
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