Question

Eight different letters of an alphabet are given. Words of four letters from these are formed. The number of such words with at least one letter repeated is

Hint:

### In the question 8 different letters are given we have to find the number of 4 letter words with at least one letter repeated this means that one letter can be repeated or two letter can be repeated or three or four but no letter repeated is not allowed. So, we will first find the total number 4 letter words formed from 8 letters then we will subtract the number of 4 letter words formed from 8 different letters with no repetition allowed.

## The correct answer is:

### Total number of 4 letter words formed from 8 different letters =

number of 4 letter words formed from 8 different letters with no repetition allowed =

So, the number of 4 letter words formed from 8 different letters with at least one letter being repeated =

### Related Questions to study

The number of 4 letter words that can be formed using the letters of the word EXPLAIN which begin with a vowel when repetitions are allowed is

As the 4 letter word has to start with a vowel,

So, the number of ways of choosing the first letter ==3

Now for the next three letters we know that any letter from the 7 letters can be used as repetition is allowed.

Therefore, the number of 4 letter words that can be formed using the letters of the word EXPLAIN which begin with a vowel when repetitions are allowed = =1029

The number of 4 letter words that can be formed using the letters of the word EXPLAIN which begin with a vowel when repetitions are allowed is

As the 4 letter word has to start with a vowel,

So, the number of ways of choosing the first letter ==3

Now for the next three letters we know that any letter from the 7 letters can be used as repetition is allowed.

Therefore, the number of 4 letter words that can be formed using the letters of the word EXPLAIN which begin with a vowel when repetitions are allowed = =1029

Which of the following statements is wrong?

Which of the following statements is wrong?

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### Cyclic polymetaphosphates have the general formula of Cyclic trimeric polymetaphosphate, is a compound heaving commercial importance. Which of the following is/are true regarding -

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Statement II Principle of conservation of momentum holds true for all kinds of collisions.

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Statement II Principle of conservation of momentum holds true for all kinds of collisions.

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### (Me)_{2}SiCl_{2} on hydrolysis will produce -

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