Question

How many ounces are in 500 mL?

Answer 1

Hint: The fluid ounce is sometimes referred to simply as an "ounce" in applications where its use is implicit.
A fluid ounce (abbreviated fl oz, fl. oz. or oz. fl.) is a unit of volume equal to $ \dfrac{1}{160} $ th part of the imperial (UK) gallon (4.54 liters), and is equal to $ \dfrac{1}{128} $ th part of the US gallon (3.78 liters).
1 ounce is about 28.4 ml in the imperial system and about 29.6 ml in the US system.

Complete step-by-step answer:
Imperial system:
We know that 28.4 ml is equal to 1 ounce.
Dividing both sides by 28.4, we get:
⇒ 1 ml is equal to $ \dfrac{1}{28.4} $ ounces.
Multiplying both sides by 500, we get:
⇒ 1 × 500 ml is equal to $ \dfrac{1}{28.4} $ × 500 ounces.
⇒ 500 ml is equal to 17.6 ounces.

US system:
We know that 29.6 ml is equal to 1 ounce.
Dividing both sides by 29.6, we get:
⇒ 1 ml is equal to $ \dfrac{1}{29.6} $ ounces.
Multiplying both sides by 500, we get:
⇒ 1 × 500 ml is equal to $ \dfrac{1}{29.6} $ × 500 ounces.
⇒ 500 ml is equal to 16.89 ounces.

Additional Information
The French revolution (1789 - 99) provided an opportunity for the French to reform their unwieldy and archaic system of many local weights and measures.
The units of the metric system, originally taken from observable features of nature, are now defined by seven physical constants being given exact numerical values in terms of the units. In the modern form of the International System of Units (SI), the seven base units are: meter (m) for length, kilogram (kg) for mass, second (s) for time, ampere (A) for electric current, kelvin (K) for temperature, candela (cd) for luminous intensity and mole for amount of substance. These, together with their derived units, can measure any physical quantity. Derived units may have their own unit name, such as the watt $ \left( \dfrac{J}{s} \right) $ and lux $ \left( \dfrac{cd}{{{m}^{2}}} \right) $ , or may just be expressed as combinations of base units, such as velocity $ \left( \dfrac{m}{s} \right) $ and acceleration $ \left( \dfrac{m}{{{s}^{2}}} \right) $ .

Note: The word "ounce" comes from the Latin "uncia" meaning "twelfth part", however its usage commonly means "a unit". It has the same origin as the word "inch" used in lengths.
The ounce is the name of several different units of mass, weight, or volume used in most British derived customary systems of measurement.
Until 1976, an imperial (UK) gallon was based on the volume of 10 pounds (4.5359 kg) of water at 62 $ {}^\circ F $ (17 $ {}^\circ C $ ).
There are two types of US gallon: liquid and dry.
Both the US liquid and imperial gallon are divided into four quarts (quarter gallons), which in turn are divided into two pints, which in turn are divided into two cups, which in turn are further divided into two gills. Thus, both gallons are equal to four quarts, eight pints, sixteen cups, or thirty-two gills.