PRACTICE GUIDE MAVEN SECURITIES
Maven Securities Probability and Problem Solving Practice Test
The Maven Securities probability and problem solving screen is 18 questions in 30 minutes - about 1.7 minutes each - answered by picking one of the options. It marks negatively, so a wrong answer costs you a mark and a skip costs you nothing.
Where it sits: Same sitting, final section. The practice sitting on this page runs the same item count, the same clock and the same marking rule, with questions generated by Outcry rather than taken from Maven Securities.
Outcry is not affiliated with Maven Securities and has no access to their assessment content. This guide describes an assessment format that candidates report publicly; the questions here are generated by Outcry and are not Maven Securities’s own.
What it screens
A London-based proprietary trading group active in derivatives market making and systematic strategies.
- ✓Expected value computed fast and used to make a decision
- ✓Conditional probability and Bayes updates without formal notation
- ✓Ranking likelihoods rather than computing them exactly
- ✓Fermi estimation: decomposing an impossible question into three easy ones
Where it sits at Maven Securities
This section does not arrive on its own. It closes the paper, and the sitting around it runs 41 minutes and 98 items in total, with Mental maths and Sequences on the same continuous clock. Candidates who prepare only for this round tend to be caught by the pacing of the rest.
There is no going back. You answer or skip, and the next item loads, which means the decision to leave an item is final at the moment you make it.
The format
These are the numbers the Maven Securities sitting on this site runs on, matching the format candidates report.
| Questions | 18 |
|---|---|
| Time | 30 minutes |
| Per question | 1.7 minutes |
| Negative marking | Yes - a wrong answer costs a mark |
| Answer style | Multiple choice |
| Where it sits | Same sitting, final section |
What it tests, with a worked example
Every example below is generated by Outcry, drawn from the same question generators the timed drills run. None of them is Maven Securities’s.
Conditional probability
Bayes' rule in disguise: a test result, a signal, a drawn card, and what it implies.
Example
Roll a fair die until every face has appeared at least once. What is the expected number of rolls?
Answer 14.7
Coupon collector: 6·(1 + 1/2 + 1/3 + 1/4 + 1/5 + 1/6) = 14.7.
Counting and combinatorics
Arrangements, selections and the complement trick that turns a hard count into an easy one.
Example
A deck has 11 ranks with 5 cards of each rank, 55 cards in all. You are dealt 5. How many different 5-card hands contain exactly four cards of one rank and one card of a different rank?
Answer 2750
Product rule again. Pick the repeated rank 11 ways, pick four of its 5 cards C(5,4) = 5 ways, then the loose card is any of the 50 cards outside that rank. 11 x 5 x 50 = 2,750.
Distributions you should know cold
Binomial, geometric and uniform means and variances, applied rather than quoted.
Example
Two return series correlate at 0.5. What share of the variance in one is explained by a linear fit on the other?
- 100%
- 75%
- 25%
- 70.7%
- 50%
Answer 25%
R² is the square of the correlation: 0.5² = 0.25, so 25%.
Estimation under uncertainty
A number nobody knows exactly, reasoned to the right order of magnitude out loud.
Example
10 people have to get across a river. The boat carries at most 2 and somebody has to row it back each time. Every crossing counts as one trip, in either direction. What is the fewest trips that gets all 10 across?
Answer 17
Count the net progress. A crossing over plus a row back moves 2 across and brings 1 home, a net gain of 1, and costs 2 trips. After 8 such rounds 8 people are across and 2 are left, which the final crossing takes in one go. So 2 x 8 + 1 = 17.
Ranking outcomes
Ordering several events by likelihood, where only the exact order scores.
Example
Stock Price DELTA $163.83 HOTEL $256.42 ECHO $205.67 CEDAR $24.18
The index above is price weighted with a divisor of 1.6253. CEDAR does a 5-for-1 split, so its price goes from $24.18 to $4.84. What is the new divisor?
Answer 1.5769
The index level cannot jump on a corporate action, because nobody's wealth changed. Before: the prices sum to $650.10 and the level is $650.10 / 1.6253 = 399.9877. After: the prices sum to $630.76. Set the new divisor so the level is unchanged: D_new = $630.76 / 399.9877 = 1.576949. Equivalently D_new = D_old x (new sum / old sum) = 1.6253 x 0.970251. Leaving the divisor alone would print a level of 388.0884, a move of -2.975% that no holder experienced. This is exactly how the Dow divisor drifted from 1 to well under 0.2.
Symmetry arguments
Questions that collapse to one line once you notice the two cases are mirror images.
Example
Three fair dice are rolled. How many of the 216 ordered outcomes total 7?
Answer 15
Counting ordered triples summing to 7 gives 15, so the chance is 15/216 = 6.9%.
What a good score looks like
On a paper of 18 questions marked +1 and -1, the arithmetic of the threshold matters as much as the threshold: every wrong answer costs you two places against someone who skipped it. Probability rounds are usually marked as part of a wider battery, so a standalone threshold is rarely reported. Where candidates do describe one it clusters around getting two thirds of the items right, with the caveat that these sections are short enough that two mistakes move you a long way.
How to train for it
- 01Work the standard results until they are recall, not derivation: complement, conditional, binomial mean and variance, geometric expectation.
- 02Do them timed. A probability question you can solve in four minutes and the paper gives you ninety seconds for is a question you cannot solve.
- 03Sanity-check the magnitude before committing. A probability above one or an expectation outside the range of outcomes is a caught error, and these papers plant both as options.
TRAIN IT HERE
The drills that match each section
Likelihood Ranking
Order events from most to least likely - the exact screen-question format.
Fermi Estimation
Piano tuners in Chicago, atoms in a body - scored on order of magnitude.
Quitters Never Lose
A casino stopping-strategy game that is secretly a martingale lesson.
Tail Risk
Rare events and fat tails, and what they do to a plain expected-value estimate.
SIT THE FULL BATTERY
All the sections back to back on one clock, marked the way the real screen marks them, with a by-skill breakdown at the end. Included with any pass.
Also reported at Maven Securities
Common questions
- Is the Maven Securities probability and problem solving test multiple choice?
- Multiple choice. You pick one option per question.
- How long is the Maven Securities probability and problem solving test?
- 18 questions in 30 minutes, which is about 1.7 minutes each.
- Is there negative marking on the Maven Securities probability and problem solving test?
- Yes. A wrong answer costs you a mark, so an item you cannot see a route through is worth skipping outright - a blind guess on this paper is negative expected value.
- How do I practise for it free?
- Every drill linked on this page is free to play, with no account, inside a daily run cap. Questions are generated fresh each run, so there is nothing to memorise between attempts. The full Maven Securities Online Assessment sitting puts the sections back to back on one clock.