99 Percentile Qs Bank for JEE MainMathematicsSets and Relations
If R be a relation from A = 1 , 2 , 3 , 4 to B = 1 , 3 , 5 such that a , b ∈ R ⇔ a < b , then R O R - 1 is
Options
- A( 1 , 3 ) , ( 1 , 5 ) , ( 2 , 3 ) , ( 2 , 5 ) , ( 3 , 5 ) , ( 4 , 5 )
- B( 3 , 1 ) , ( 5 , 1 ) , ( 3 , 2 ) , ( 5 , 2 ) , ( 5 , 3 ) , ( 5 , 4 )
- C( 3 , 3 ) , ( 3 , 5 ) , ( 5 , 3 ) , ( 5 , 5 )
- D( 3 , 3 ) , ( 3 , 4 ) , ( 4 , 5 )
Correct answer
C. ( 3 , 3 ) , ( 3 , 5 ) , ( 5 , 3 ) , ( 5 , 5 )
Step-by-step solution
A = 1 , 2 , 3 , 4 and B = 1 , 3 , 5 ∴ R = ( 1 , 3 ) , ( 1 , 5 ) , ( 2 , 3 ) , ( 2 , 5 ) , ( 3 , 5 ) , ( 4 , 5 ) and R - 1 = ( 3 , 1 ) , ( 5 , 1 ) , ( 3 , 2 ) , ( 5 , 2 ) , ( 5 , 3 ) , ( 5 , 4 ) Now, 3 → R - 1 1 → R 3 ⇒ 3 , 3 ∈ R O R - 1 5 → R - 1 1 → R 5 ⇒ 5 , 5 ∈ R O R - 1 5 → R - 1 2 → R 3 ⇒ 5 , 3 ∈ R O R - 1 3 → R - 1 1 → R 5 ⇒ 3 , 5 ∈ R O R - 1 ∴ R O R - 1 = 3 , 3 , 3 , 5 , 5 , 3 , 5 , 5