Old Mission · OA
In processOld Mission Capital QT OA :35 MCQ
This is a summary based on publicly available interview reports for the Old Mission Capital Junior Quant Trader OA.
1. OA Format
Based on reports from 2024 New Grad Junior Quant Trader candidates:
- Around 35 multiple-choice questions + 1 coding problem
- The multiple-choice section was roughly 25–35 minutes
- The coding section was around 30 minutes
- Python was recommended for the coding portion
- Calculators were allowed
- Probability answers were usually expected in simplified fractions or exact decimals
One thing that comes up repeatedly in candidate reports is that speed is the biggest challenge.
Most individual questions are not extremely difficult, but there are a lot of them, so spending too much time on the first 10–15 questions can hurt you later.
The coding section seems relatively manageable time-wise. A simple working solution is usually better than spending too much time trying to fully optimize it.
Some candidates who moved on to later rounds also reported questions involving probability, mental math, and situational/behavioral questions.
2. Publicly Reported Question Types & Answers
Here are some examples that have appeared in public reports:
-
Two dice sum to 8:
Answer: 5/36 -
26 people all shake hands with each other once:
Answer: C(26,2) = 325 -
1/50 products are defective. You earn $3 on a good product and lose $75 on a defective one. What is the expected profit?
Answer: $1.44 -
Given that two dice sum to 9 and one of the dice is a 5, what is the probability of the possible outcome?
Answer: 1/2 -
Pick a random card numbered 1–30 and receive 6 times the number on the card:
Expected value: $93 -
Draw from two containers. Probability of getting the same color:
Answer: 37/72 -
Choose two numbers without replacement from 1–15. Probability their sum is odd:
Answer: 8/15 -
Probability that the first two cards drawn from a standard deck are both Jacks:
Answer: 1/221 -
Flip a fair coin five times. Probability all five flips are the same:
Answer: 1/16 -
Flip two coins. You win $2 for each head, but lose $7 if both are tails. Expected value:
Answer: $0.25 -
Probability that HHH appears before TTTT:
Answer: 15/22 -
There are 3 large donuts and 9 small donuts, with a process continuing until only small donuts remain. Expected time:
Answer: 131/12 ≈ 10.917 hours
Old Mission Capital QT OA Questions
2025 (Jul–Sep)
Role: Quant Finance / New Grad
Reported in April, 2025Format: 35 questions in 25 minutes
Question 24 is missing here, but it was reportedly very easy.
Question List
1. Dice Sum
What is the probability that the sum of two dice is 8?
2. Handshakes
In a group of 26 people, if everyone shakes hands with everyone else exactly once, how many handshakes occur in total?
3. Expected Profit
A company manufactures widgets, but 1 out of every 50 is defective.
- Profit on a working widget: +$3
- Loss on a defective widget: -$75
What is the expected profit per widget?
4. Conditional Probability with Dice
I just rolled a total of 9 with two dice.
What is the probability that one of the dice showed a 5?
5. Expected Value of a Card Game
There are 30 distinct cards numbered from 1 to 30.
You draw one card uniformly at random, and I pay you:
6 × the number on the card
What is the expected value of this game?
6. Matching Ball Colors
Jar A
- 3 red balls
- 5 black balls
Jar B
- 4 red balls
- 5 black balls
If one ball is drawn at random from each jar, what is the probability that the two balls are the same color?
7. Odd Sum
A jar contains 15 balls, numbered from 1 to 15.
Two balls are drawn without replacement.
What is the probability that their numbers sum to an odd number?
8. Pair of Jacks
What is the probability that the first two cards drawn from a standard deck are both Jacks?
9. Five Identical Coin Flips
A fair coin is flipped 5 times.
What is the probability that all five flips show the same side?
10. Fair Value of a Coin Game
A player flips 2 coins.
- Win $2 for each head
- Lose $7 if both coins are tails
What is the fair value of this game?
11. Double-Headed Coin
A jar contains 12 coins:
- 10 fair coins
- 2 double-headed coins
One coin is chosen at random and flipped 5 times.
All five flips are heads.
What is the probability that the selected coin was double-headed?
12. Repeated Half-Bankroll Betting
You start with $64 and make 6 consecutive bets.
On every bet, you wager half of your current bankroll.
If you win 3 times and lose 3 times, how much money do you gain or lose?
13. Safe vs. Unsafe Drivers
An insurance company knows:
- Unsafe drivers have a 40% chance of an accident in a year
- Safe drivers have a 10% chance
- 85% of drivers are safe
Given that a driver had an accident, what is the probability that the driver is unsafe?
14. Ordered Ball Draws
A jar contains:
- 7 red balls
- 10 black balls
Four balls are drawn without replacement.
What is the probability that:
- The first two are red
- The next two are black
15. Shoes Without a Complete Pair
A closet contains 5 pairs of shoes.
If 5 individual shoes are selected at random, what is the probability that no complete pair is selected?
16. Pair from a Deck
What is the probability that the first two cards drawn from a standard deck form a pair?
17. HH Before TH
You and your friend repeatedly flip a fair coin.
- If
HHappears first, you win - If
THappears first, your friend wins
What is the probability that you win?
18. Horse Race
There are 8 horses in a race.
What is the probability that:
- Horse #4 finishes second
- Horse #1 finishes in the top three
19. Expected Losing Score
A fair coin is flipped repeatedly.
- Heads → I get 1 point
- Tails → You get 1 point
The game ends when either player reaches 3 points.
What is the expected score of the loser?
20. Three Dice Sum
Three fair dice are rolled.
What is the probability that their sum is 14?
21. Party Invitations
A person has 9 friends and wants to invite 6 of them.
Two of the friends do not get along and will not attend together.
How many valid invitation groups are possible?
22. Circular Bracelet
How many distinct circular bracelets can be made using:
- 3 red beads
- 3 green beads
23. Blackjack Probability
What is the probability of being dealt a blackjack?
A blackjack means drawing:
- One Ace
- One card from
10, J, Q, K
The two cards are drawn without replacement.
24. Skipped
Question 24 was not included in the report.
25. Palindromes of MISSISSIPPI
How many palindromic arrangements can be formed using the letters in:
MISSISSIPPI
26. Exactly Two Majors
A university offers only three majors:
- Computer Science
- Mathematics
- Philosophy
The student population is distributed as follows:
- 50% major in Mathematics
- 60% major in Computer Science
- 20% major in Philosophy
- 6% major in all three
What percentage of students major in exactly two subjects?
27. Fair Value of an Option-Like Right
An energy company is drilling for oil.
- Probability of success: 35%
- Probability of failure: 65%
- Stock value if successful: $100
- Stock value if unsuccessful: $16
- Current stock price: $58.50
You have the right to buy the stock for $70 on the day after the drilling result becomes known.
What is the fair value of this right?
28. Party on the First Sunny Day
You want to host a party over the weekend.
- Probability of rain on Saturday: 70%
- Probability of rain on Sunday: 60%
You will hold the party on the first day without rain.
By Monday, you know the party happened and your friends enjoyed it.
What is the probability that the party was held on Saturday?
29. Same Row or Column
Two squares are selected uniformly at random from an 8×8 chessboard.
What is the probability that the two selected squares share the same:
- Row, or
- Column
30. Another Pair After Two 8s
Two cards are drawn without replacement from a standard 52-card deck.
The first two cards are both 8s.
You then draw two more cards.
What is the probability that the next two cards also form a pair?
31. Last Red Ball by Draw 5
A bag contains:
- 3 red balls
- 5 black balls
Balls are drawn one at a time, uniformly at random, without replacement.
What is the probability that the last red ball is drawn on or before the 5th draw?
32. First Ace Appears at Position 33
A standard shuffled deck is revealed one card at a time.
The first Ace appears as the 33rd card.
What is the probability that the 34th card is the 7 of Diamonds?
The answer is not
1/51.
33. Candy Conveyor Belt
On a candy conveyor belt:
- 4 out of every 5 chocolates are followed by a jelly bean
- 2 out of every 3 jelly beans are followed by a chocolate
What fraction of all candies on the conveyor belt are jelly beans?
34. HHH Before TTTT
You and your friend repeatedly flip a fair coin.
- If
HHHappears first, you win - If
TTTTappears first, your friend wins
What is the probability that you win?
35. Homer and the Donuts
A box contains:
- 3 large donuts
- 9 small donuts
Every hour, Homer randomly selects one donut.
- If it is a small donut, he eats it
- If it is a large donut, he cuts it in half:
- eats one half
- puts the other half back as a small donut
What is the expected number of hours until the box contains only small donuts?
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