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How many 4-letter code can be formed using the first 10 letters of the...

How many 4-letter code can be formed usi | Class 11 Mathematics Chapter Permutations & Combinations, Permutations & Combinations NCERT Solutions

Question:

How many 4-letter code can be formed using the first 10 letters of the English alphabet, if no letter can be repeated?

Answer:

There are as many codes as there are ways of filling 4 vacant places

in succession by the first 10 letters of the English alphabet, keeping in mind that the repetition of letters is not allowed.

The first place can be filled in 10 different ways by any of the first 10 letters of the English alphabet following which, the second place can be filled in by any of the remaining letters in 9 different ways. The third place can be filled in by any of the remaining 8 letters in 8 different ways and the fourth place can be filled in by any of the remaining 7 letters in 7 different ways.

Therefore, by multiplication principle, the required numbers of ways in which 4 vacant places can be filled is 10 × 9 × 8 × 7 = 5040

Hence, 5040 four-letter codes can be formed using the first 10 letters of the English alphabet, if no letter is repeated.

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NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

Read the question carefully and focus on the core concept being asked.
Reference examples and data from the chapter when answering questions about Permutations & Combinations.
Review previous year question papers to get an idea of how such questions may be framed in exams.
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Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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Ayush
2018-09-19 21:23:11

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Welcome to the NCERT Solutions for Class 11 Mathematics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 3: How many 4-letter code can be formed using the first 10 letters of the English alphabet, if no lette....

How many 4-letter code can be formed usi | Class 11 Mathematics Chapter Permutations & Combinations, Permutations & Combinations NCERT Solutions

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