MindMath Pro vs Probability Paradox Lab

Train for the real quant and consulting interview tests, then keep going into the interview that follows them. MindMath Pro rebuilds the actual numerical tests firms use, with their real timing and scoring. Run the Optiver 80-in-8, the Flow Traders 75-in-10 and the IMC 24-in-18, then see how your score compares with everyone else who took the same test. The online test is only the first round. Round 2 adds 40 probability and expected value questions from the interview that comes after it, covering expected value, waiting times, conditional probability, counting and the classics that come up again and again. They are untimed, because they are meant to be thought about, and each one comes with the full working rather than just the answer. Free to start, no account needed: Speed Benchmark. Two minutes, as many as you can, the standard mental maths speed score. One free run of each firm simulator (Optiver, Flow Traders, IMC). The first three Round 2 questions. Number sense drills for percentages, fractions, decimals, sequences and case math. Smart Practice, plus stats that find your weakest operation and send you back to it. An interview countdown plan from today to test day, and on into Round 2 prep afterwards. Pro unlocks the reps: Unlimited runs of every firm simulator. All 40 Round 2 questions with full worked solutions. Hard and Quant difficulty. The full tricks library and advanced analytics: average answer time, weakest times-tables and one-tap weakness drills. Unlimited daily volume. Free is capped at 30 problems and 3 sessions a day. Seeing a question once does not make you faster, but doing five hundred does. The free app shows you the gap. Pro is how you close it. Built for candidates sitting tests at Jane Street, Optiver, SIG, Citadel, Flow Traders, IMC, McKinsey, Bain and BCG. Pricing: a weekly plan with a 3-day free trial, a monthly plan, and a one-time Interview Crunch pass that unlocks everything for 30 days with no auto-renew, for when your test is close. Subscription details: MindMath Pro offers auto-renewable weekly and monthly subscriptions, plus a one-time 30-day Interview Crunch pass which does not auto-renew. Prices are shown in the app. A 3-day free trial is available on the weekly plan for new subscribers. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period, and your Apple ID is charged for renewal within 24 hours of the period ending. You can manage or cancel anytime in your App Store account settings. Privacy Policy: https://catrin12.notion.site/Privacy-Policy-MindMath-Pro-2f0e07388cb0801e91daddb09e5f8347?pvs=74 Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

"With 23 people in a class, what's the chance two share a birthday?" The answer exceeds 50%. Were you surprised? Probability Paradox Lab is an interactive app that lets you experience mathematical paradoxes through simulation — results that feel wrong, yet are mathematically proven. [ HOW IT WORKS ] 1. Make your intuitive guess 2. Run the simulation and see the real result 3. Read the math explanation and understand why Be surprised by the answer. Be surprised again by the explanation. [ FREE THEMES ] Birthday Problem (Free) With just 23 people, the probability of a shared birthday exceeds 50%. Why? Monty Hall Problem (Free) After the host opens a losing door, switching wins 2/3 of the time. Mathematically proven — yet deeply counterintuitive. Two Envelopes Problem (Free) A seemingly valid argument says you should always switch envelopes. Where's the flaw? Coupon Collector Problem (Free) Collecting all 10 kinds takes about 29 pulls on average. Fast at first, then it stalls. [ PREMIUM THEMES ] One-time purchase unlocks 12 more paradoxes and Quiz Mode across all themes. No subscriptions, no ads for premium users. Ellsberg Paradox Why do people prefer known odds over unknown ones — even when the math says they're equal? Boy or Girl Paradox "One child is a boy." How does that single fact change the probability? False Positive Paradox A 99%-accurate test says positive for a disease 1% of people have. You're sick with only ~50% odds. Gambler's Fallacy Five heads in a row. Is tails due? Randomness is clumpier than it looks. St. Petersburg Paradox Expected value is infinite, yet you'd pay little to play. Why? Nontransitive Dice (Efron-style) A beats B, B beats C, C beats A. No die is the strongest. Parrondo's Paradox Two losing games, played in alternation, somehow become a winning strategy. Simpson's Paradox A treatment wins in every subgroup — yet loses overall. How? Secretary Problem Interview one at a time with no going back. The optimal strategy for catching the best. Benford's Law About 30% of naturally occurring numbers start with a 1. A curious statistical bias. Friendship Paradox Your friends have more friends than you — the network bias that makes it true. 100 Prisoners Problem If even one fails, all are executed. Yet one strategy saves everyone about 31% of the time. [ PERFECT FOR ] - Math & statistics enthusiasts - Curious minds who love "why?" - Brain teaser & trivia fans - Students and lifelong learners