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Question: Answered & Verified by Expert
If $A=\{(a, b): 4 a=5 b ; a, b \in\{1,2,3, \ldots 30\}\}$, then the number of such ordered pairs $(a, b)$ is
MathematicsSets and RelationsJEE Main
Options:
  • A 4
  • B 6
  • C 8
  • D 10
Solution:
2358 Upvotes Verified Answer
The correct answer is: 6
(b) The only possible pairs are:
$(5,4),(10,8),(15,12),(20,16),(25,20),(30,24)$

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