Goldman Sachs Summer Analyst - Equity Research interview questions

I did not go to superday because I applied cross-continent. My ACs were done through email. They had a video interview after CV selection, and then a case study via email. The final round of interview consists three 1 to 1 interview.

Met with an MD at my school for first round. He asked me if I liked sports and what I liked to do in my spare time. The case he gave me was as follows. Three companies in Brazil make a product. Two are private. One public. 90% of their customers are in the US, and the exchange rate between Brazil and the US changes. How does this change price? (It doesn't.) How does the firm decide the ideal level of profit it wants? (Return on Equity)