ta se lay duong dat tren chiet can dia roi dat qua can 1 kg vao dia con lailam sao cho 2 ben dc can =
cu nhu vay lam 3 lan thi ta dc 3 kg.
den lan thu 4 ta se lay so duong ra =1/2 qua can nag 1kg
vay da lay dc 3,5 kg = 1 chiec can dia & 1 quacan nag 1kg
sai thi thoi nha