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Let the relation R be defined in N by aRb if 2a + 3b = 30. Then R = ______.

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Question

Let the relation R be defined in N by aRb if 2a + 3b = 30. Then R = ______.

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Solution

Let the relation R be defined in N by aRb if 2a + 3b = 30. Then R = {(3, 8), (6, 6),(9, 4), (12, 2)}.

Explanation:

Given that, 2a + 3b = 30

3b = 30 – 2a

b = `(30 -2"a")/3`

= `10 - (2"a")/3`

Since 'a' and 'b' are natural numbers, 'a' must be multiple of '3'

For a = 3, b = 8

a = 6, b = 6

a = 9, b = 4

a = 12, b = 2

R = {(3, 8), (6, 6),(9, 4), (12, 2)}

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Chapter 1: Relations And Functions - Exercise [Page 16]

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NCERT Exemplar Mathematics Exemplar [English] Class 12
Chapter 1 Relations And Functions
Exercise | Q 48 | Page 16

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