Latest Infosys Aptitude Question SOLUTION: When all the possible 5 letters are arranged in the letter LASER in alphabetical order,what will be the 25th word and 16th word?

---- Basic Logic ----
For this type of Q's think about a dictionary, which you have to crate using the given word.
---- Answer ---
According to dictionary letter "A" appears first.
So, A _ _ _ _ position of A is fixed. Now we can shuffle the rest of the letters in remaining 4! ways i.e. 24 words can be created when A will be at 1st position.
So the 25th word will now begin with the next letter i.e. E
so, alphabetically the 25th word will be "E A L R S"

In the similar way go for 16th word,
The 1st word will be "A E L R S"
now at first changing only last 2 letters so 2! ways i.e 2 words [A E L (R S) & A E L (S R) ]
now considering the next change, last 3 letters will get shuffled in 3! ways i.e 6 new words will get created.
So the last 6th word will be "A E (S R L)".
In a similar way proceeding the 12th word is "A (L S R E)". Now the letter next to A will get changed to next one i.e R. So, the 13th word will look like "A R E L S", all are in the dictionary format and are in alphabetical manner.
From here just make 3 more word by interchanging letters following the alphabetical way,
So, the words will look like as,
>> 14th word = " A R E S L"
>> 15th word = " A R L E S"
>> 16th word = " A R L S E"
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So, the final answer is 25th word = EALRS & 16th word = ARLSE
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aelrs is the alpha bectically sorted string
a---- is sorted by 4!( factorial) ways
so the next one is ealrs.

16th- ALRSE
25th- EALRS

hey can anyone explain this clearly

answer is ealsr!!!

(26C1*25C1*2!) * (10C1*9C1*2!) Is the answer .. Here 2! Is multiplied the two alphabets can b interchangeable as well as the two numbers