Investment Banking Analyst

I emailed the firm's general recruitment email with my resume and a brief cover letter in the body of the email. They contacted my a day later to schedule and conducted the interview about 4 days after my initial email. I had 1 interview with 2 MDs at the firm. The questions were a bit difficult. You have to focus on the small details of it. In my opinion, the BIWS wasn't enough to prepare for this.
Example: How do you forecast revenue in a financial model without making a growth rate assumption. Or how do you make that assumption?