Let R be a relation from N to N defined by R = {(x, y): x, y ∈ N and x2 = y³}. Which of the following are not correct?

1. (x, x) ∈ R for all x ∈ N

2. (x, y) ∈ R ⇒ (y, x) ∈ R

3. (x, y) ∈ R and (y, z) ∈ R ⇒ (x, z) ∈ R

Select the correct answer using the code given below :

Consider the following :

1. A ∩ B = A ∩ C ⇒ B = C

2. A ∪ B = A ∪ C ⇒ B = C

Which of the above is/are correct ?

How many received medals in exactly two of the three sports ?

How many received medals in at least two of three sports ?