Q: You need to weigh up to 40 kg with 4 weights. What should be the weigh of each of weight? A: 1 kg, 3 kg, 9 kg, 27 kg Solution : 1 : 1 kg 2 : (3 -1) Kg 3 : 3 Kg 4 : (3+1) Kg 5 : (9-(3+1)) Kg 6 : (9-3) Kg 7 : ((9+1)-3) Kg 8 : (9-1) Kg 9 : 9 Kg and so on..