Well, seriously, you might get asked brainteaser questions like these, especially in quantitative jobs. But remember that the interviewer doesn’t necessarily want an exact number—he wants to make sure that you understand what’s being asked of you, and that you can set into motion a systematic and logical way to respond. So, just take a deep breath, and start thinking through the math. (Yes, it’s OK to ask for a pen and paper!)
Tip: It’s easy to get hung up on figuring out your single most impressive accomplishment. Instead, think of a few achievements that showcase your work ethic and values. If you can, pick examples that also tie back to the job you’re applying for. The STAR method is a great tool to ensure you highlight not only your role but how you drove business results. 
You have explained that you are looking for a sales executive who is able to effectively manage over a dozen employees. In my 15 years of experience as a sales manager, I have developed strong motivational and team-building skills. I was twice awarded manager-of-the-year for my innovative strategies for motivating employees to meet and surpass quarterly deadlines. If hired, I will apply my leadership abilities and strategies to achieve profit gains in this position.
You don't need to memorize an answer, but do take the time to consider how you'll respond. The more you prepare, the more confident you'll feel during a job interview. When you're not sure what to expect during an interview, also take time to review this refresher on how job interviews work, and these tips on how to prepare to ace your job interview. 

Rarely do candidates come to the end of an interview feeling they've done their best. Maybe the conversation went in an unexpected direction. Maybe the interviewer focused on one aspect of their skills and totally ignored other key attributes. Or maybe candidates started the interview nervous and hesitant, and now wish they could go back and better describe their qualifications and experience.

Interview Questions Which Animal Would You Be?

“I’ve heard great things about the work environment here from a few colleagues. And when I saw this job posting, it seemed to match my skills very closely. For example, I saw on the job description that you need somebody who’s an expert in Java programming. This is what I focused on in both of my previous positions, and was even the focus of my academic work before graduating university. I consider myself an expert in Java and it’s a skill I hope to continue specializing in.”
Here are the 50 most frequently-asked questions that are posed in interviews. Be prepared to go into some detail about your work history; you may also be asked behavioral or situational questions which require you to provide an anecdote about how you have handled a work challenge in the past or, alternatively, how you would approach a situation in the future.