A={1,2,3,4,5…,M}
B={1,2,3,4,5…,N}
where N is an even number and M is an odd number

Quantity A- percentage of odd numbers in set A
Quantity B- percentage of even numbers in set B

The answer to this question is A. Can someone please explain what is the process?

Also, how do we know whether set A and set B contain an equal number of terms?

Let M = (say) 11 and N = (say) 10. What do you get?

If M=11 and N=10, option A is correct

However, if the values are reversed, the B should be true, right?

Also, are these sets necessarily in AP?
I mean cant they be like-
A= {1,2,3,4,5,29,79,100}

Which you can’t.

They are in an arithmetic progression indeed, with common difference of 1.

gupta.abhinav857:

I mean cant they be like-
A= {1,2,3,4,5,29,79,100}

No, that’s not possible here. The question could admittedly be a bit more clear on that aspect, by saying something that references the first m positive integers.

Since there is no relation between M and N, if M is 11 and N is 20, then obviously B will be greater. So shouldn’t the answer be ‘D’?