A collection of quant riddles with answers
There's a reference to the classic <i>Heard on the Street</i> book but you should also check out Zhou's green book, which consists a guide on cracking the type of interview questions Google used back in the mid 2000s/early 2010s (how many ping pong balls can fit in an airplane), with much more demanding problems though:<p><pre><code>    A Practical Guide To Quantitative Finance Interviews,  Xinfeng Zhou
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<a href="https://www.amazon.com/Practical-Guide-Quantitative-Finance-Interviews/dp/1438236662" rel="nofollow noreferrer">https://www.amazon.com/Practical-Guide-Quantitative-Finance-...</a>