Investment Banking Summer Analyst

This was a second round interview for the role of an Investment Banking Summer Analyst. There were four back-to-back 30 min interviews, each of them VERY technical. The only relevant experience I had was an IBD Spring Week, but I guess they assumed that I gained in-depth valuation skills from it. I'd read up on valuation methods, calculating WACC etc, but the interviews were focused on really in-depth usage of the various valuation methods. There were a fair few questions that I didn't immediately know the answer to, but I thought through them out loud, attempting to answer them in a logical manner. I think that is the best way to approach the difficult questions asked that you don't immediately know the amswer to.