Choose the correct option. On an average, a content developer can develop $6$ questions in an hour. Resource manager wants to complete the project of $2400$ questions in $20$ hours. How many developers should he take in his team?

The correct option is B

$20$

Given: one person can work for one hour and develop $6$questions.

Assume that there are $x$ persons in the team.

Now, $x$persons had to work for $20\text{\hspace{0.17em}hours}$ to complete $2400$ questions.

Therefore,

$\begin{array}{l}x\times 6\times 20=1\times 2400\\ \Rightarrow x=\frac{1\times 2400}{6\times 20}\\ \Rightarrow x=\frac{2400}{120}\\ \Rightarrow x=20\end{array}$

So, he should take $20$ developers in his team.

Hence, the correct option is (B).