While you don't need an MBA, you must understand how money moves.
For mental math, use apps or trainers to reduce your response time. 150 Most Frequently Asked Questions On Quant Interviews
If you are interested in developing these types of systems as a career, consider reading Quantitative Trading: How to Build Your O... While you don't need an MBA, you must
"I’d short the stock at $10.05 to delta-neutral, then adjust based on my inventory. If I have positive gamma from options, I’d hedge dynamically." While you don't need an MBA
These questions assess your ability to think on your feet. The goal isn't always the "right" answer, but the logical path you take to get there.