Which of the following is a mixed number?

A mixed number is a combination of a whole number and a proper fraction. In this case, the correct answer is 3 1/5, which consists of the whole number 3 and the fraction 1/5. This representation shows that there are 3 whole parts and an additional fraction, making it a mixed number.

The other choices are entirely improper fractions or simple fractions. The option 32/36 simplifies to 8/9, which is a proper fraction. The option 19/5 is an improper fraction (greater than 1) but does not contain a whole number along with a proper fraction, thus not qualifying as a mixed number. Lastly, 6/24 simplifies to 1/4, also a proper fraction. Therefore, they do not fit the definition of a mixed number.