Find the number of ways all 9 letters of the word EVERGREEN can be arranged if (i) there are no restrictions, (ii) the first letter is R and the last letter is G, (iii) the Es are all together. Three letters from the 9 letters of the word EVERGREEN are selected. (iv) Find the number of selections which contain no Es and exactly 1 R. (v) Find the number of selections which contain no Es.​

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Answer: ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ 

Step-by-step explanation:

The word EVERGREEN can be arranged in the following manner.

What is Arrangement?

The number of possible arrangements or orders for a set of items is known as an arrangement number, also known as a permutation number or just a permutation.

  • Step 1: When there are no restrictions

The letter EVERGREEN has 9 letter. So, the total arrangements will be 9!.

But letter 'E', 'R' are repeating 4 times and 2 times respectively.

Thus, total arrangements becomes 9!/(4!×2!) =  7560.

  • Step 2: When the first letter is R and the last letter is G

As, first and last letter are fixed for R and g respectively.

Thus the total positions left are 7! with  'E', 'R' are repeating 4 times and 2 times respectively.

Thus, total arrangements becomes 7!/(4!×2!) =  105.

  • Step 3: When the Es are all together. Three letters from the 9 letters of the word EVERGREEN are selected.

The total combination for arrangement is 7560.

But when all 4 E's are kept together its gives 4! = 24.

Therefore, the total combination becomes 7560×120 = 181440.

  • Step 4: When the number of selections which contain no Es and exactly 1 R.

As, no E and 1 R is not to be taken which left 5 positions with no repetitions of letter

Thus, the total combination becomes 4! = 24.

  • Step 5: The number of selections which contain no Es.​

The total letter left after the removal of all 4 E's is 5 with times repetition of R.

Therefore, the total combination will be 5!/2! = 60.

To know more about permutation and combinations, here

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