Understand it. Then drill it.
Every lesson covers one interview topic, question type by question type: the intuition, why it works, a worked example with live numbers, diagrams you can move, the same idea run backwards, and a check marked exactly like practice.
Quant Finance topic lessons
4 of 4 topics readyProbability
The six calculations behind most quant probability questions: counting outcomes, the shape of a sum, sequences of flips, waiting times, the price of a bet, and updating a belief when the alarm fires.
- 1Counting: does order matter?
- 2Two dice: why the total is a triangle
- 3Coins: counts, complements and waiting for a pattern
- 4How long until it happens: 1 ÷ p
- 5Pricing a bet: expected value and the noise around it
- 6The alarm fired. How worried should you be?
Brainteasers
The two mechanisms behind most puzzle questions, with live numbers: price an option to try again by working backwards, and turn a rate puzzle into one division by holding the relative speed. The classic puzzles that do not change are on the Concepts page.
- 1What is a second try worth? Price it backwards
- 2Clock hands: relative speed in a costume
Options & Greeks
From the price that needs no model to the contest a hedged option is really about: parity, payoffs at expiry, the square root of time, implied against realized volatility, delta hedging, and gamma against theta.
- 1Put-call parity: the price that needs no model
- 2Spreads at expiry: add up the hockey sticks
- 3An at-the-money option and the square root of time
- 4Implied against realized: a price against a measurement
- 5Delta hedging: right for an instant
- 6Gamma against theta: the contest a hedged option is about
Statistics
The five statistics calculations quant interviews come back to: scaling risk with the square root of time, combining two assets, splitting one asset's risk into market and own, the standard error of a mean, and whether a Sharpe ratio is real.
- 1The square root of time
- 2Two assets: covariance, the minimum and the spread
- 3Beta, R-squared and what a hedge cannot touch
- 4How sure is the average? The standard error
- 5Is a Sharpe ratio significant? t = Sharpe × √years