The number of relations, defined on the set {a, b, c, d which are both reflexive and symmetric, is equal to:}
Show Hint
Memorize the relation counting formulas for a set of $n$ elements: Total relations = $2^{n^2}$, Reflexive = $2^{n^2-n}$, Symmetric = $2^{\frac{n(n+1)}{2}}$, Both Reflexive and Symmetric = $2^{\frac{n(n-1)}{2}}$.