# Preguntas de entrevista de Operations analyst

# 7 mil

Preguntas de entrevista para Operations Analyst compartidas por los candidatos## Principales preguntas de entrevista

### 25 horses, 5 race tracks. How many races you have to run to select top 5 horses.

51 respuestas↳

You guys are not doing CS! 10 runs is my answer. 1. randomize 5 groups, each of 5 horses 2. rank them within each group, I will use Anuradha's notation (5 races) 3. pick the best of each group, race to figure the 1st place, call it A1 (1 race) It should be clear, it wins all times, every one lost once. 4. remove it. substitute 2nd best in. repeat 3 (in my eg. A2,B1,C1,D1,E1) now you have second place. keep going, you get the first 5 and ranking! So, 5+5=10 races in total. Menos

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The answer is 9. Assuming: - There's no time measuring (stopwatch), just relative places. - The horses perform consistently. - A maximum of 5 horses per race. First we need 5 races (A to E) to get relative scores for all 25 horses. Let's take a worst scenario: the list was already ordered (A1 fastest and E5 slowest), so race A contained the top 5. The 6th race would be the winners of the 5 races (A1, B1, C1, D1, E1), and would give A1 as the fastest of all. This would also mean that some horses can be excluded (only 4 more places to fill): B5 C4, C5 D3, D4, D5 E2, E3, E4, E5 For the 7th race, A2 would replace A1, and A2 would be appointed as the runner-up (of all). We also can exclude some more (only 3 more places to fill): B4 C3 D2 E1 For the 8th race, A3 would replace A2, but as E1 has been excluded, we got a vacancy. Let's add C2 for worst case scenario. The winner would be A3, and we can exclude more horses (only 2 more places to fill): B3 C2 D1 At this point there're only 5 horses who have not yet been classified or excluded, so the winner and runner-up of the 9th race would give 4th and 5th overall. Menos

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Anuradha's solution still has problems. (Even if we go with Anuradha's assumptions that you can only race one horse per track, and also assuming that we don't have a stopwatch and must compare horses placing positions) What if the fastest five horses are A1, B1, C1, D1, and E1 ? In Anuradha's second step, he elminates two of the fastest horses (D1 and E1) . He's assuming that A2, B2, or some of the other horses from the other heats are faster, but he hasn't actually tested to see if that is true. Menos

### Rate yourself on a scale of 1 to 10 how weird you are.

15 respuestas↳

One number lower than whoever came up with this question

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about a 5.6719151431

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I am within two standard deviations from the norm...

### CASE: Cross-selling Credit Insurance to Cardholders direct mail: .50, 1% response rate, avg balance $1000, 5% claim insurance, etc. Profitable? How make more profitable? What if response rate doubled but claims doubled? Make chart of profit curve, what does it mean if..., etc.

12 respuestas↳

Thanks for your response and guidance. I knew the revenue is monthly, but i thought claim rate is also monthly and hence calculated profit for each credit insurance sold per month. In light of your clarification Profit per card insurance per year = (10*12)-50-50 = 20$ per year If we chose to calculate per month, we will need to consider monthly claim rate as (5/12) and also amortize the marketing expense over next 12 month. Profit per card insurance per month = 10-(50/12)-(50/12)= (20/12)$ per month The profitability equation (per card per year) = 120x-10xy-50 For calculating any of the break even rates (x or y assuming 1 is known), 120x-10xy-50 = 0. For graph, P = 120x-10xy-50 Let me know if my analysis/answer is accurate and up to the mark. Thanks a lot for all your guidance. Menos

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@ ghachla: The response rate is 1% that is 1 out of 100. I assumed 100 people are sent the mail. Hence the response rate is 1. As for the claim rate, the people who don't respond can't make claims. So out of the people who respond, the claim rate is 5% (i.e 1 person responds in 100 and out of that 1, 0.05 make the claim); Or to make it more clearer, if we assume 10000 people are sent the mail, 100 respond (because of the 1% response rate) and 5 out of the 100 make claims (because of the 5% claim rate). Menos

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Looks like I left out the price of the insurance: customers would pay 1% of monthly balance for insurance. Menos

### You have the choice between using first class or third class mail for a letter you are sending out to potential customers. First class costs $0.50 per piece and reach 100% of potential customers. Third class costs $0.40 per piece and reaches 80% of potential customers. Which do you use?

10 respuestas↳

either one is good. For example, you will reach 0.8 person by spending $0.4. If divided 0.4 by 0.8, we get that we will reach 1 person by spending $0.5. So two methods have the same effect. Menos

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First class should be used, as the cost of each delivered letter will be the same, but you will reach all of your intended audience. Example: 1000 pieces to be sent, sending first class costs $500 and reaches 1000 ($.50 per peice), and sending second class costs $400 and reaches 800 ($.50 per piece) Menos

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@gaurav: don't make it too complicated. they just want to know the costs of reaching the customers. peppermint is right. Menos

### What is the fastest amount of time you can get 4 people across a bridge. Each person takes a different amount of time .. 1 minute, 2, 5, and 10. They can cross 2 at a time but need a flashlight to cross.

9 respuestas↳

It's 17 minutes. The actions are of the form (x, y, ->) or (x, ), (1, ), (2,). Sum up the maximum of each tuple and get 17! Menos

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17. 1 and 2 go together for 2 min. 1 runs back for 3 min. 5 and 10 run across for 13 min, 2 runs back for 15 min and 1 and 2 run across for 17 min. Menos

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No, its 17!

### Pretend 1% of the population has a disease. You have a test that determines if you have that disease, but it's only 80% accurate and 20% of the time you get a false positive, how likely is it you have the disease.

8 respuestas↳

1%. The first sentence gives you all the info you need.

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1% chance if using global population. Chances would decrease or increase depending on certain variable or demographic factors so I would say you need more data to give a specific answer. Things like age , gender , race , need to be taken into consideration if you are a 33 year old male and the subject disease is ovarial cancer then you have 0 percent chance . If you are a 40 year old nun and the disease is The clap you have less probably of being infected than say a 26 year old prostitute .. Menos

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Sample: 1,000 X=10 P=.8 If the test is only 80% accurate then 8 of the 10 infected will be positive and 2 will walk around unbeknownst, but 20% of the non-infected population will be falsely identified, 1000-10=990 (non-infected) 990*.2=198 (false positive) + 8 (true positive)= 296 (total positive tests) Of this population only 8/296=2.7% were correctly identified. This is the chance you have the disease Menos

### What are the number of new customers needed in order to break even?

6 respuestas↳

@ Interview Candidate : How did you even get to 8000? Did you know what was the profit per new applicant? Menos

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It's over 9000!

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Can you please explain how you calculated the breakeven to be 8000 or 9000??

### Given two different mailing options with different cost rates and effectiveness rates, which option would be best in various scenarios? (For example, unlimited mailing list, unlimited budget, have both be unlimited, specific numbers of each, etc.

5 respuestas↳

They let you use a calculator if you bring one.

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For unlimited budget, the price doesn't matter so we choose the mailing option with the higher effectiveness rate. Is this correct? I'm confused with the scenario "specific number of budget". Say we want to optimize the number of successful mailing response. This number N should be = fund * effectiveness rate / cost rate. Then N is actually nothing to do with the fund. Which mailing method can have a bigger N depends on the ratio effectiveness rate / cost rate. Is this the right way to solve the problem? Menos

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If you use regression analysis or dynamic range function analysis you are more likely to get an unbounded answer. I would stick with Cartesian power thermos. Menos

### What would you choose between your family and job?

5 respuestas↳

I choose job because for family there is many person in my family to handel them , my first preference is my job Menos

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I will give my 100 when i m wd my family and when i m at ofc

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I will give my 100 percent when i m with my family and when i m at work bcoz both are important aspects of life and both are dependent on me and needs my time and attention Menos