KVPY2020MathematicsSets and Relations
Let A be a set consisting of 10 elements. The number of non-empty relations from A to A that are reflexive but not symmetric is
Options
- A2 89 - 1
- B2 89 - 2 45
- C2 45 - 1
- D2 90 - 2 45
Correct answer
D. 2 90 - 2 45
Step-by-step solution
n ( A × A ) = 100 number of a ,   a type pairs is 10 number of ( a , b ) and ( b , a ) type pair of pairs is 45 ( a ≠ b ) so, required number of relations is 2 90 - 2 45