NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 1: Real Numbers
Exercise 1.4 - Long Answer Questions

Question. 1

Show that the cube of a positive integer of the form \(6q + r\), where \(q\) is an integer and \(r = 0, 1, 2, 3, 4, 5\), is also of the form \(6m + r\).

Answer:

Yes. The cube of such an integer is again of the form \(6m + r\).

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Question. 2

Prove that one and only one out of n, n + 2 and n + 4 is divisible by 3, where n is any positive integer.

Answer:

Exactly one out of n, n + 2 and n + 4 is divisible by 3.

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Question. 3

Prove that one of any three consecutive positive integers must be divisible by 3.

Answer:

Yes, in every set of three consecutive integers, one of them is divisible by 3.

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Question. 4

For any positive integer \(n\), prove that \(n^3 - n\) is divisible by 6.

Answer:

Yes. For every positive integer \(n\), the number \(n^3 - n\) is divisible by \(6\).

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Question. 5

Show that one and only one out of n, n + 4, n + 8, n + 12 and n + 16 is divisible by 5, where n is any positive integer.

Answer:

Exactly one and only one out of n, n + 4, n + 8, n + 12 and n + 16 is divisible by 5.

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NCERT Exemplar Solutions Class 10 – Mathematics – CHAPTER 1: Real Numbers – Exercise 1.4 - Long Answer Questions | Detailed Answers