That's going to be heavily dependent on what you plan to pack into the suitcase. If the allowable limit is 20 kg, you can do that with books or rocks in just a small suitcase, but you'll need a considerably bigger one to achieve it with underwear.
90 kg
No, its weight is 16.15 kg
About 64 kg for a man that size
1 kg = 2.2 pound 23 pounds = 23 (pounds) x (1/2.2) (kg/pound) = 23/2.2 kg = 10.4545 kg
There is luggage available that only weighs about 3 kg empty.
As, we know that, 1 pound = 0.453592 kg So, 23 pound = 0.453592 kg x 23 Thus, 23 lbs = 10.43 Kg
20 liters of water (at sea level)
You can, if size, weight and contents fit within the airline's regulations.They're typically something like this:Maximum size:23 cm x 40 cm x 55 cm(9 in x 15.5 in x 21.5 in)Wheels and handles included.Maximum weight:10 kg (22 lb)Small regional planes may not allow any carry-on luggage.
66Kg You really cannot tell how much the suitcase can hold in mass. 66 litres is the volume of the suitcase. The answer would be 66 kg if you were carrying water, but I think the actual weight limit is going to be far less, otherwise the suitcase would be capable of carrying the weight of a typical teenager (145 lb)
23 L
It is 50.706 lbs (approx.). Kilogram is the SI unit of mass and pound is an imperial unit of mass. To convert from kg to pound, multiply the kg unit by 2.20462.