Free GMAT Practice Question

A vat holds $60$ litres of a syrup-and-water mixture that is $25\%$ syrup by volume. Farida draws off $12$ litres of the mixture and replaces it with $12$ litres of water, stirring until the vat is uniform again. She then draws off $12$ litres of the resulting mixture and replaces it with $12$ litres of pure syrup, once more stirring until uniform. Syrup is what percent of the final $60$ litres by volume?