https://www.interviewquery.com/p/trading-interview-probability-questions the kindle book https://jerryqin.com/posts/a-working-list-of-probability-problems

Two gamblers are playing a coin toss game. Gambler A has fair coins; B has fair coins. What is the probability that A will have more heads than B if both flip all their coins.

Source: Xinfeng Zhou



A casino offers a simple card game. There are 52 cards in a deck with 4 cards for each value … The cards are thoroughly shuffled, so that each card has an equal chance of being selected. You take a card from the deck first, and the dealer takes another without replacement. If you have a larger number you win; if the numbers are equal or yours is smaller, the house wins. Does the house have the better odds of winning? If so, what is your probability of winning?

Source: Xinfeng Zhou

☞ The house has better odds of winning

☞ Break it down into what happens for each scenario (each card picked first)

☞ For example, what is the probability of you winning if you select a

☞ Now do this for each card (2, 3, …, Ace)

☞ And then simply multiply by your probability of choosing each card in the first place



ELO

ELO ratings

The core idea behind ELO is:

A concept - if you repeat unough events which hav e asuper slim chance of happening, you wil see a few, in aggregate
Random walks
Brownian motion (toms questions)
Amanda’s the Hopeless Romantic

Let’s say we have a friend Amanda u wished to vecome someone. now, if true