Question

Let $A=\{1,2,3,4,6\}$. If $R$ is the relation on $A$ defined by $\{(a,b):a,b\in A,b$ is exactly divisible by $a\}$.
Assertion (A) The relation $R$ in Roster form is $\{(6,3),(6,2),(4,2)\}$
Reason (R) The domain and range of $R$ is $\{1,2,3,4,6\}$

• A. Both A and R are correct; R is the correct explanation of A
• B. Both A and R are correct; $R$ is not the correct explanation of $A$
• C. $A$ is correct; $R$ is incorrect
• D. $R$ is correct; $A$ is incorrect

Answer 1

Answer: (D)

In Roster form $R=\{(1,1),(1,2),(1,3),(1,4),(1,6)$, $(2,4),(2,6),(2,2),(4,4),(6,6),(3,3),(3,6)\}$
Domain of $R=$ Set of first element of ordered pairs in $R=\{1,2,3,4,6\}$
Range of $R=\{1,2,3,4,6\}$