How many pints are equivalent to $3$ gallons?

Hint: In this sum the only thing the student should know about is the unit of measurement. It is important to know that Gallon is a unit of measurement for volume and fluid capacity. From the question, if the student has an idea about the unit of measurement for gallon, he can gage that Pint would also be a unit of measurement for volume and capacity. Though there is a direct conversion from pint to gallon, a step by step approach would be beneficial to remember the conversion. First method is finding a relation between $1$ pint to $1$ gallons. And then multiplying by $3$. Another method is to first bring pint in terms of gallon by finding relations between cups, pints quarts and then gallon. Finally multiplying it by $3$ to come to the desired answer.

Complete step-by-step answer:
First method is direct application of the conversion. Though this is difficult to remember this would give an answer very quickly.
It is said that $8$ pints is equivalent to $1$ gallon.
Now to find the number of pints equivalent to $3$gallons, we multiply by $3$, in order to get the value for $3$ gallons.
$\therefore 24p\operatorname{int} s$= $3$gallons.
Second method is to follow a step by step approach as given below:
It is said that
$2cups = 1$Pint.........(1)
$2$Pint= $1$ quart.........(2)
$4$quart = $1$ gallon.........(3)
Thus , from the equation $1,2,3$, we can find the relation between Pints and gallons.
From equation $2\& 3$ we can say that $4$ quarts =$8$ Pints........$(4)$
Therefore Comparing the LHS of Equation $3\& 4$, we can establish the following relation
$1$ gallon = $8$ Pints........$(5)$
Thus $3$ gallons is equal to $24$ pints.
Answer is $24$ pints.

Note: Though this is an easy numerical, the questions asked are in terms of word problems where the student has to apply this conversion in order to calculate the volume. It may so happen that the student might have to convert Pint to Litre directly. In such a case it is advised to first convert Pint to gallon and then from gallon to litre. It is always beneficial to remember the direct value for conversion instead of following the second method given in the solution above.