To find out how many pints are equal to 10 liters, you can use the ratio of 1 liter to 2.1 pints.
Multiply 10 liters by the conversion factor:
\[ 10 , \text{liters} \times 2.1 , \text{pints/liter} = 21 , \text{pints} \]
Therefore, 10 liters is equal to approximately 21 pints.