Let $I$ be an ideal of a ring $R$. Then Show that $|(R/I)| = 1 $ if and only if $R = I$.

Question

(i) Show that $|(R/I)| = 1 $ if and only if $R = I$.

(ii) Show that if $R$ has an identity 1 then (if $I \neq R$) so does $R/I$, and if $R$ is commutative, then so is $R/I$.

I know that the quotient ring of $R$ by $I$ is defined to be $R/I = \{a+I : a\in R\}$. but I am not sure what to do for either part here.