2) An item has been discounted by $20 \%$ of its original price. By what percentage must it be increased to regain the original price?
(A) $16 \%$
(B) $20 \%$
(C) $25 \%$
(D) $50 \%$
(E) $60 \%$.
2) The answer is (C). Indicating with $p$ the percentage of recharge and with $P$ the original price, we have $P\left(1-\frac{20}{100}\right)\left(1+\frac{p}{100}\right)=P$, from which $p=25 \%$.