Reema types 540 words during half an hour. How many words would she type in 6 minutes ?

Suppose she types x words in 6 minutes. Then, the given information can be represented in the following tabular form :
$\begin{array}{ccc}\text{Number of words}& 540& x\\ \text{Time (in minutes)}& 30& 6\end{array}$
Since in more time more words can be typed, it is case of direct variation.
$\therefore$ Ratio of number of words = Ratio of number of minutes
$\Rightarrow \frac{540}{30}=\frac{x}{6}\Rightarrow x=\frac{6\times 540}{30}\Rightarrow x=108$
Hence, she types 108 words in 6 minutes.