There are three ways of mixing the teas. Taking them in the order of
quality, 2s. 6d., 2s. 3d., 1s. 9p., mix 16 lbs., 1 lb., 3 lbs.; or 14
lbs., 4 lbs., 2 lbs.; or 12 lbs., 7 lbs., 1 lb. In every case the
twenty pounds mixture should be worth 2s. 4½d. per pound; but the last
case requires the smallest quantity of the best tea, therefore it is
the correct answer.