51 gram == 1.8 oz
volume
Sulfur is closely match this puzzle. The density of 2 kg sulfur is double than 1 kg water. So if you weigh the sulfur in immersed state, the weight of sulfur will be 1 kg. Sulfur will displace about 1 kg water and will lose the same weight. After taking out of water, 2 kg sulfur will be 2 kg only. When you burn the sulfur, it will combine with 2 kg oxygen and you will get 4 kg of sulfur bi oxide. So it is fairly close to the answer. 3 kg literally means more than 2 kg. May be you know the better answer.
1 kg
That would be 2 Kg (on earth)
12 kg in weight, exactly.
None. Costliest page may be US$100 per kg. Gold is around US$40,000 per Kg.
The weight of Olympic Gold is about 158000 mg or 0.158 kg or simply about 158 grams.......
18.9 kg
20 kg
Weight(mass) is measured in kilograms.
Bucket plus Water = B + W = 50 kg Bucket + 0.5*Water = B + W/2 = 30 kg Subtracting the second equation from the first gives W/2 = 20 kg So W = 40 kg Then B + W = 50 kg gives B = 10 kg.
135 kg of water