Write as percent
A.$\dfrac{{42}}{{100}}$
B.$\dfrac{{73}}{{100}}$
C.$\dfrac{6}{{100}}$
D.$\dfrac{{15}}{{100}}$

Hint: A fraction can be converted into percent by multiply the fraction with 100 and is given by
\[ \Leftrightarrow \dfrac{a}{b} \times 100 = \dfrac{{a \times 100}}{b}\% \]
E.g. $\dfrac{2}{5}$is converted into percent by multiplying it with 100.
$\dfrac{2}{5} \times 100\% = 2 \times 20\% = 40\% $

Complete step-by-step answer:
You can also convert fraction into percent by first converting that fraction into decimal and multiply it with 100. E.g. convert \[\dfrac{3}{4}\] into percent
$
   \Leftrightarrow \dfrac{3}{4} = 0.75 \\
   \Leftrightarrow 0.75 \times 100\% = 75\% \\
$
While solving option A first of all, convert the fraction into decimals we get
A) $\dfrac{{42}}{{100}} = 0.42$
Now, convert this decimal into fraction by multiply it with 100
$ \Leftrightarrow 0.42 \times 100\% = 42\% $
While solving option B first of all, convert the fraction into decimals we get
A) $\dfrac{{73}}{{100}} = 0.73$
Now, convert this decimal into fraction by multiply it with 100
$ \Leftrightarrow 0.73 \times 100\% = 73\% $
While solving option C first of all, convert the fraction into decimals we get
A) $\dfrac{6}{{100}} = 0.06$
Now, convert this decimal into fraction by multiply it with 100
$ \Leftrightarrow 0.06 \times 100\% = 6\% $
While solving option D first of all, convert the fraction into decimals we get
A) $\dfrac{{15}}{{100}} = 0.15$
Now, convert this decimal into fraction by multiply it with 100
$ \Leftrightarrow 0.15 \times 100\% = 15\% $

Note: We can convert percent into fraction by dividing the number by 100.
In our daily life, percentage plays an important role. It is almost used in every sector. For understanding the financial aspect of our daily life, percentage plays an important role.
If you want to compare two things then percentage is used. E.g. the growth of a company can be analysed by seeing percentage increase or decrease in the sales of the company. The formula for percentage increase is given below:
$ \Leftrightarrow Percentage\, increase/decrease = \dfrac{{CurrentSales - \ Previous\, Sales}}{{\ Previous\, Sales}} \times 100$