Let $\displaystyle G$ be a finite group. Let $\displaystyle n_{p}$ denote the number of p-sylow subgroups. Prove that if $\displaystyle n_{p} \ncong 1 \ (mod \ p^{2} ) $ then there exists p-sylow subgroups P and Q of G such that $\displaystyle |P:P \cap Q|=|Q:Q \cap P|=p $