Zeal Test Series 2019: Set Theory & Algebra - Binary Operation

Question

 

Comments

yeah only i) and ii ) satisfied the condition

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Only ($ii,iii$) satisfy both the conditions. $2$ is correct answer.

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@Deepakk Poonia (Dee)

Please Explain ???

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@deepak bro I got the second one and i know I) and 4) are not satisfying

But i am not getting iii) m*n=36 n*m =36 so commutative

For associativity -m*(n*p)=m*36

(m*n)*p =36*p

Then how to proceed next it is said that i *is binary operation on natural numbers