Given : A={x:xϵN and 11≥2x−1} and B={y:yϵW and 3≤y≤9}.
For A,
11≥2x−1
⇒12≥2x
⇒6≥x
Natural numbers less than and equal to 6 are 1,2,3,4,5,6
Hence, A={1,2,3,4,5,6}
For set B,
3≤y≤9
Whole numbers between 3 and 9 , including them are 3,4,5,6,7,8,9
Hence, B={3,4,5,6,7,8,9}
Number of elements in A is 6 and in B is 7.
Hence, they are not equivalent sets.