Let A={a,b,c,d,e,f} R⊂A×A,R is reflexive, ⇒(x,x)∈R‌∀x∈R ⇒(‌6C1)⇒6 elements We need 4 elements but since R is symmetric, we want to pairs (α,β) and (γ,δ) such that (α,β)∈R and (γ,δ)⇒(β,α)∈R and (δ,γ)∈R ⇒ We need to choose the pairs (α,β) and (γ,δ) ⇒ Total unordered pairs ⇒‌6C2=15 pairs Out of these we need two pairs ⇒‌‌‌15C2=‌