Ban Mai dung 25000dong mua but .Co hai loai but :loai 1 gia 2000dong 1 chiec, loai 2 gia 1500 dong 1 chiec . Ban Mai mua duoc nhieu nhat bao nhieu but neu :
a) Mai chi mua but loai 1?
b) Mai chi mua but loai 2?
c) Mai mua ca hai loai but voi so luong nhu nhau?