Question

How many millilitres are in 4.8 gallon? (1 gallon = 3.8 L and 1L=1000ml)

Answer 1

Hint: First derive and write the unitary relationship between the unit gallons and milliliters. Then use that relation to form a conversion relation from gallons to milliliters. Then modify that relation for one unit of gallon to milliliter. Then multiply the given gallons in the previous step to obtain the required answer.

Complete step by step answer:
In the metrics system, many types of measurements units are used according to their ease of use. Some are used for measurements of wide ranges such as kilometers, miles and many used for precise measurements such as millimeters, milliliters.
Gallon is used to measure quantities like weight, capacity. It is represented by the symbol $(gal)$ . Milliliter is \[1/1000th\] of a liter that means $1L=1000ml$ . Also $1gal=3.8L$ . So $1gal=3.8\times 1000ml$ .
So, we got a relationship between milliliters and gallons and we are for conversion of gallons to milliliters
Now we got the relation for one unit of gallon to milliliter. To find $4.8$ gallons in milliliter, multiply both sides by $2$ we get,
\[\Rightarrow 1\times 4.8gal=3.8\times 4.8ml\]
$\Rightarrow 4.8gal=18.24ml$
So $4.8$ gallon is equal to $18.24ml$ .

Note:
There are some basic rules for converting one unit to another. If you need to convert a larger unit into a small unit then multiply with the appropriate value. If you need to convert a smaller unit into a large unit then divide with the appropriate value. The value is the number which relates those units with one another.