Co' 3 cai ly
Ly 1 chua' dc toi da 12 lit nuoc
Ly 2 chua' dc toi da 7 lit nuoc
Ly 3 chua' dc toi da 5 lit nuoc
Cho 12 lit nuoc, cac ban hay~ rot' sao cho cuoi' cung` co' 1 ly 6 lit
Luu y': ko do~ ra ngoai`, chi rot' qua lai giua 3 ly ko co' ly thu' 4.
Luc rot' phai~ day` ly dc nhan nuoc hoac ly rot' thi` viec rot' nuoc moi ngung lai
Vi du li 7 lit rot qua li 5 lit' thi` li 7lit con` lai 2 lit
li 5 lit rot qua li 7 lit thi` li 5lit het' nuoc', li 7 lit co 5 lit. OK BABY