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JEE Main
Exam
JEE Main
Subject
Mathematics
Chapter
Sets and Relations

JEE Main · Mathematics · Sets and Relations

If A=\ (a, b): 4 a=5 b ; a, b ∈\ 1,2,3, 30\ \ , then the number of...

If A={(a,b):4a=5b;a,b∈{1,2,3,…30}}A=\{(a, b): 4 a=5 b ; a, b \in\{1,2,3, \ldots 30\}\}, then the number of such ordered pairs (a,b)(a, b) is

Options

  1. A4
  2. B6
  3. C8
  4. D10

Correct answer

B. 6

Step-by-step solution

(b) The only possible pairs are: (5,4),(10,8),(15,12),(20,16),(25,20),(30,24)(5,4),(10,8),(15,12),(20,16),(25,20),(30,24)
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