Question

If A = {Prime numbers less than 10}, and B = {Positive odd numbers less than 10}, then find (i) A ∩ B (ii) B – A.

Answer 1

A = {Prime numbers less than 10} and 

B = {Positive odd numbers less than 10} 

∴ A = {2, 3, 5, 7},B = {1,3,5, 7, 9} 

∴ (A ∩ B) = {2, 3, 5, 7} ∩ {1,3, 5,7, 9} = 

{3,5,7} — (1)

and (B – A) = {1, 3, 5, 7, 9} – {2,3, 5,7} = 

{1,9} —–(2)