Goldman Sachs Interview Question

1 St Round - Only Math puzzles such as how can you calculate time using 2 burning threads. 2nd Round - Implement stack using 2 queues, delete a node in a linked list, desing SQL database for a company 3rd Round (the Hiring manager ) - How to find the odd one out of ball out of 9 balls in 3 steps, difference between compile time and runtime exception