UPSC NDA I 2021 Mathematics Solved Paper

Concept
Equivalent set: When two sets, for example, A and B have the same cardinality if there exists an objective function from set A to B are called Equivalent set, i.e n(A)=n(B)
Equal set: Two sets for example A and B can be equal onlyif each element of set A is also the element of the set B. If two sets are the subsets of each other, they are said to be equal. So, it can be written as,
A=B
A⊂B and B⊂A⇔A=B
Calculation:
From the definition of equivalent and equal set we can see that;
Statement 1 is true because the number of elements in A= Number of elements in B=3
Statement 2 is true because {1,5,9}∈A and {1,5,9}∈B