Question

A petrol tanker contains $20,000$ litre of petrol, expresses the quantity of petrol, in kilo litre and millilitres.

Answer 1

Hint: We are given a tanker has $20,000$ litre of petrol, we have to express this quantity into kilolitre and millilitre, to do this we learn about dimensional analytics, we will learn how are kilolitre is connected to like, we will learn relation between millilitre and litre than we use those relation to find the solution. We will use $1KL=1000L$ and $1mL={{10}^{-3}} L$ using these we find our solution.

Complete step by step solution:
We are given that a tanker contains $20,000$ litre of petrol, we have to convert this to 1) kilolitre and 2) millilitre
Before we start, first we learn about dimensional analysis.
Now dimensional analysis also known as unit factor method is a problem-solving method that uses for fact that my number in expression can be multiplied by one without changing its value. It is a great technique to change the dimension of one quantity, quantity remains same, but just dimensional will get changed. For example, we know in $100cm$, so $1m=100cm$. Then quantity is the same just dimension is different.
Now we learn about how kilolitres is related to litre. Kilo in term to represent $1000$ of any quantity kilogram mean $1$ thousand grams
So, Similarly
Kilo litre means $1000$ litre. So we get
$1KL=1000L$
Now we use unitary method as
$1000L=1KL$
So, find the value of $1L$ in terms of KL so divide both sides by $1000$.
Hence we get,
$1L=\dfrac{1}{1000}KL$
Now as total volume is $20,000$ litres.
So, multiply above by $20,000$ we get,
$20,000=20,000\times \dfrac{1}{1000}KL$
Simplifying we get,
$20,000L=20KL$
So, $20,000$ litre is the same as $20$ kilolitre.
2) now we learn how millilitre is joined to litre.
Millilitre is used to denote by $1000=\dfrac{1}{1000}$
For example, millimetre means= $\dfrac{1}{1000}m$
Similarly, millilitre means $\dfrac{1}{1000}litre$
$1ml=\dfrac{1}{1000}litre$s
Now we use the unitary method, we will multiply by $1000$ to find the value of $1$ litre. So, we get
$1L=100mL$
Mean in $1$ litre then one $1000ml$ so, for $20,000$ litre, we multiply both side by $20,000$ so, we get,
$20,000\,litre=20,000\times 1000ml$
Simplifying we get,
$\begin{align}
  & 20,000\,litre=2,00,00,000ml \\
 & \Rightarrow 2\times {{10}^{7}}ml \\
\end{align}$
Hence in $20,000$L there is $2,00,00,000ml$.

Note: Remember that we need to be careful while multiplying when we change a big unit to the small then it will get a little large to calculate so from many arrive. Also, we cannot skip any between units, we always need to change the term unit by unit. It's widely used in chemistry to change the number of atoms to mole or change larger units into small ones.