PRACTICE GUIDE OLD MISSION
Old Mission Quantitative Practice Test
Outcry’s Old Mission quantitative practice section has 25 questions in 35 minutes. These numbers describe the linked mock; the source check below distinguishes published details from practice settings.
The two clocks, question mix, language, navigation and scoring are Outcry settings, not a verified universal Old Mission screen.
Outcry is not affiliated with Old Mission 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 Old Mission’s own.
What it screens
A Chicago-based options market maker and hedging firm trading listed derivatives across global exchanges.
- ✓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 Old Mission
No current firm-published specification for this exact 25-question quantitative and one-question coding combination was verified.
Practice stage: Quantitative & coding practice · round unconfirmed. The two clocks, question mix, language, navigation and scoring are Outcry settings, not a verified universal Old Mission screen.
The format
These are the settings used by Outcry’s Old Mission practice sitting. They are not automatically the employer’s published format; see the linked assessment’s source check.
| Questions | 25 |
|---|---|
| Time | 35 minutes |
| Per question | 84 seconds |
| Negative marking | No |
| Answer style | Multiple choice |
| Where it sits | Quantitative & coding practice · round unconfirmed |
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 Old Mission’s.
Conditional probability
Bayes' rule in disguise: a test result, a signal, a drawn card, and what it implies.
Example
You have one fair six-sided die and need a uniform random number from 1 to 7. Which procedure works?
- Roll twice and take the larger, mod 7, plus 1
- Roll twice and take the sum mod 7, plus 1
- Roll once and multiply by 7/6, rounding
- Roll twice for 36 outcomes; re-roll on the last one, map the other 35 into 7 groups of 5
Answer Roll twice for 36 outcomes; re-roll on the last one, map the other 35 into 7 groups of 5
36 outcomes can't split into 7 equal groups, but 35 can (7×5). Discard one outcome and re-roll - the sum-mod-7 trick fails because sums are not uniform.
Counting and combinatorics
Arrangements, selections and the complement trick that turns a hard count into an easy one.
Example
A counter sits on square 2 of a row numbered 0 to 12. Each tick it moves one square left or one square right with equal probability, and it stops on 0 or on 12. What is the probability it stops on 12?
- 5/6
- 1/7
- 1/6
- 1/2
Answer 1/6
The position itself is a martingale in a fair walk, so its expected stopping value equals its start: p x 12 + (1 - p) x 0 = 2, giving p = 2/12 = 1/6. Step size does not enter it.
Estimation under uncertainty
A number nobody knows exactly, reasoned to the right order of magnitude out loud.
Example
Whole numbers are picked one at a time, and you get to keep picking. How many do you have to pick to be certain that two of them leave the same remainder when divided by 18?
Answer 19
The remainders are the 18 boxes, 0 through 17. Picking 18 numbers can dodge a repeat exactly once, by hitting every remainder, so 19 forces one. The same statement says two of the picks differ by a multiple of 18, which is how this argument usually turns up.
Ranking outcomes
Ordering several events by likelihood, where only the exact order scores.
Example
A. two dice summing to 8 B. no heads in 4 coin flips C. two dice summing to 7
Rank most likely to least likely:
- A > C > B
- B > A > C
- C > B > A
- C > A > B
Answer C > A > B
A: 13.9% · B: 6.3% · C: 16.7%
Waiting times and repeated trials
How long until the first success, and why the answer is rarely the average you expected.
Example
A trading floor has 40 people on it. What is the chance that at least two share a birthday, as a percentage?
Answer 89
There are C(40,2) = 780 pairs, each matching with probability 1/365. P(none) ≈ e^−2.14 ≈ 0.12, so about 88%.
Reading the question exactly
At least, exactly, and given that - the three phrases that change the answer entirely.
Example
A price rises 58% in one quarter and then falls 40% in the next. What is the net change over the two quarters?
- -5.2%
- 18%
- -23.2%
- -18%
Answer -5.2%
100 goes to 158, then loses 40% of 158, landing at 94.8. Net -5.2%. The naive answer 18% misses the cross term, which is -23.2%.
What a good score looks like
Use this mock’s score and worked review to identify skills to practise. No Outcry score guarantees a pass or a hiring outcome; a current employer threshold for this practice paper has not been verified.
How to train for it
- 01Practise setting up before calculating. Most wrong answers on these are a correct calculation of the wrong quantity.
- 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.
- 03Work the complement first whenever the question says at least or at most. It is usually the shorter route and it is almost always the intended one.
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 Old Mission
Common questions
- Is this Old Mission’s official quantitative test?
- No. Outcry generates its own questions. No current firm-published specification for this exact 25-question quantitative and one-question coding combination was verified. The two clocks, question mix, language, navigation and scoring are Outcry settings, not a verified universal Old Mission screen.
- How long is this quantitative practice section?
- 25 questions in 35 minutes in the Outcry mock. These are practice settings unless the source check explicitly confirms them.
- How is the practice marked?
- Correct answers earn 1 mark unless the question states another weight. Wrong answers lose 0; unanswered items lose 0, including timeouts. These rules apply to this mock.
- Where can I check the employer’s process?
- See the public source check on the linked assessment. Your role-specific invitation governs the actual format, permitted tools and scoring.