Problems

118 curated questions across 15 topics, each with hints and a worked solution, including at 24 firms.

– of 118 solved

Easy –/53Medium –/52Hard –/13

/

22 results

Expected Value & Decision Theory

Medium#10
Roll Once, Maybe Reroll
Citadel · Jane Street · Squarepoint Capital
Expected Value · Numerical · 6 min
Easy#11
Hats Returned at Random
Expected Value · Numerical · 4 min
Easy#12
Kelly Bet on a Biased Coin
Expected Value · Numerical · 5 min
Medium#13
Seeing Every Face
Expected Value · Numerical · 6 min
Medium#47
Die Game with Two Rerolls
Jane Street · Susquehanna (SIG)
Expected Value · Numerical · 6 min
Easy#51
The Advantage of Flipping First
Jane Street
Expected Value · Numerical · 4 min
Medium#52
Thirty-Sided Die vs Twenty-Sided Die
Jane Street
Expected Value · Numerical · 8 min
Medium#53
Square, Product or Median Squared?
Jane Street
Expected Value · Multiple choice · 6 min
Hard#54
100-Sided Die, Rerolls Cost a Dollar
Jane Street
Expected Value · Numerical · 12 min
Hard#56
Add One or Invert
Jane Street
Expected Value · Numerical · 15 min
Hard#60
Seeing Every Face Twice
Citadel Securities
Expected Value · Numerical · 15 min
Easy#63
Accepting a Doubled Bet
Susquehanna (SIG)
Expected Value · Numerical · 4 min
Easy#64
Even Faces Pay Double
Susquehanna (SIG)
Expected Value · Numerical · 5 min
Hard#67
Tying Spaghetti into Loops
Hudson River Trading
Expected Value · Numerical · 10 min
Easy#72
Counting Switches in Coin Flips
J.P. Morgan
Expected Value · Numerical · 3 min
Easy#75
Twenty per Head or Five Hundred for Four
Akuna Capital
Expected Value · Multiple choice · 3 min
Medium#77
Uniforms Until the Sum Exceeds One
Two Sigma
Expected Value · Numerical · 8 min
Easy#81
Paid for Every Point Over Ten
DRW
Expected Value · Numerical · 5 min
Medium#84
Three Consecutive Hidden Cards
Optiver
Expected Value · Numerical · 8 min
Easy#98
Expected Gap Between Two Dice
Jane Street
Expected Value · Numerical · 3 min
Easy#102
Average Maximum of Two Uniforms
Squarepoint Capital
Expected Value · Numerical · 3 min
Medium#110
Apples Left in the Basket
WorldQuant
Expected Value · Numerical · 5 min