Kilometers.
miles?
You would use the metric unit "liters" to measure the capacity of a hot water tank.
It would probably be miles.
Metres or kilometres in metric; yards or miles in Imperial
Miles is best.
Pints
its liters
Kilogram
Metres or kilometres in metric; yards or miles in Imperial
You don't, miles are not a unit in the metric system. All distances are measured in metres. Prefixes are used for multiples or fractions of a metre. Distances that used to be measured in miles would, today, be measured in kilometres.
1 US gallon = 3.78541178 liters. Only if you mean pure water, then 1000 litres of water weighs 1 metric tonne. 1000 litres of water are 264.172052357 gallons that weigh 1 metric tonne.
The letter "k" is used to denote the metric prefix kilo (1000), which is a metric prefix. you would not measure miles in kilomiles. But if you were to, 50k miles would be 50,000 miles.