The Interview Question from BlackRock Everyone Fails at

[@anthonygg_]

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[@mrmadhan8557]

I will use hash map

[@anthonygg_]

LMAO. This is actually funny

[@cipherlofi6453]

@@anthonygg_ how about using linked list concept, idk it may sound silly but if I do say for one murderer he will be killed if he scape and if the guy next to him escape, and the chain continued?

[@ktxed]

You're hired!

[@medalikhaled]

I'll remind them that death is certain and no human has achieved immortality before.

[@MarcinCebula]

Turn the prisoners against each other and make them think that one of them will betray the other. Everyone wants to escape. No one person wants to die.

[@geoblk3000]

Finally! Something I went to school for, I graduated economic informatics in uni :) This is purely a statistical question and one from game theory mainly one of the most popular classic one called the Prisoner's Dilemma. I'm having a hard time believing NOT ONE interview candidate at BlackRock heard about it... The gist of the Prisoner's Dilemma is that to have the best outcome all agents (prisoners) must stay silent or in other words cooperate amongst them. This question is very similar given that all agents (murderers) are making rational decisions: Having one bullet and ONE murderer means that that chance of survival is 0%, hence the murderer will not try to escape, having one bullet and TWO murderers the chance of survival is 50% UNLESS the guard states that ANY of the murderers trying to escape will be shot, reducing their chance of survival back to 0% by introducing an uncertainty element into the "gameplay". Extrapolate this problem to a 100 murderers by assigning a number to each one and introduce the uncertainty element by stating that the prisoner with the smallest number will be shot, so murderer 1 will surely not move, murderer 2 knows that murderer 1 cannot move so murderer 2 will not move either and so on... As with any game theory problem there is a best and worst outcome for every agent in the game, the worst outcome for the guard would be if all 100 murderers would escape all at once, incidentally that is the best outcome for the murderers, circling back to the Prisoner's Dilemma where the best outcome for the prisoners is if they stay silent.

[@thebirdhasbeencharged]

enough yap just shoot one and put the fear of god in the other 99

[@Etrader2k7]

For me, the answer is you don't need to. My thinking is linked to the 2nd sentence: "If any *one* of the murderers has a non-zero probability of surviving, he will attempt an escape." This leads me to consider each murderer's probability to survive individually rather than as a group. If they worked as a group, they could just swarm to escape and some would make it. A variable we'd need to know in this case is the chance of killing per shot. We don't have this and I don't think it matters as far as the question is concerned. An assumption we could make is that if we shoot the gun, we kill the murderer we're aiming at. We could also assume that the murderers know about the gun. With these two assumptions, any murderer's chance of death is 100% if they are shot at meaning they will not attempt an escape. Realistically, I don't think there is a right or wrong answer to the question. It seems to be more about discussing the scenario and understanding how an analyst thinks. (Wrote this before watching. Interestingly I didn't consider the psychological aspect, I just thought about probabilities as that was what was given in the question.)

[@evertonalmeida1165]

I came up with the same solution lol. But i have no idea why they ask these kind of questions. It doesn't even make sense.

[@walt]

You stop them from escaping by letting them go free. The definition of escape is to break free from confinement or control. If you voluntarily let them go then they are not escaping. That's the only way to answer the question in a mathematical sense that I can think of.

[@keith_emerson]

You put them in a very small corridor, where the first one needs to step out so the second one can escape and so on

[@notoriouslycuriouswombat]

just make an example of one ez

[@DETahaX]

"false hope"

[@MoltenSamurai]

I can’t believe I actually had the same thought process as you here. I might go further and have all the people stand in an arc in my field of view, so it’s even more apparent that I can make good on the threat.

[@ArcticPrimal]

You cant stop them from escaping. On the Why, its up to the interviewer to choose what they have preselected to be the correct Why answer but all the Why answer will be correct

[@anthonygg_]

True, but the "why" can tell them a lot about the reasoning capabilities of the person that's in front of them.

[@MasterSergius]

It's a new season of Squid Game?

[@evolagenda]

First thought is make it a sniper on high, if none of them know who the gun is pointed at them they all have to be 0. I thought about this from the perspective of watching items in an array with pointers. 100 items 100 pointers. But only 1 pointer is the gun. It can skip around randomly but 99 pointers are always just "eyes" that keep the probability at zero. Which is probably total bullshit but it's how I thought about it.

[@gageracer]

You do what they did to Desmond in Lost. Give them a reason to not run away or it's 100% death anyway. Make them believe this is the best and only option: to stay here and live.

[@John-h2r8x]

Strictly speaking, to estimate the probability one needs to witness at least one (suffice for 100% or

[@SirSomnolent]

Let them naturally segregate. Pull the leaders of the groups aside and tell them that you got a call and due to the extraordinary circumstances, the state is providing 10 pardons along with financial reparations for wrongful imprisonment if they're able to keep the prisoners in line. Whatever leaders remain can decide who gets the pardons. No punishment for any actions they have to take. Let them work out the details

[@richardmetzler7119]

"If a murderer is certain of death, he will not attempt an escape." - Since everyone - especially murderers who took somebody's life - are certain that they will die one day, nobody will attempt to escape.

[@cipherlofi6453]

everyone will die one day. but what do you do on escaping context

[@richardmetzler7119]

@@cipherlofi6453 this is a boolean logic puzzle. Because a murderer is certain of death, he doesn't attempt to escape.

[@denissorn]

I just check what are standard suggested solutions for this problem and it's ridiculously unrealistic and crazy assumptions are made to support the "Nash equilibrium" 'solution'. If we ignored that the crucial details like the size and shape of the enclosure, the fences, and the surrounding environment is missing, I would say the obvious move would be to deceive them. You could even give the one-bullet gun to the most respected individual among them to convince them that you are on their side. (And who knows? Considering it’s fiction, anything could happen as the story unfolds.)

[@Diego-em1mb]

But what if two people tries to Escape then their probability of surviving will be 50% so they will try to escape, because you have to deside how are you gonna shot, i do believe that the problem is not there, but when you have to shot the bullet, let's say that we put ourselves on the entrance of the Jail of the Murderers and we say how ever tries to cross the door i will shot him, and there is just enough space for one person to come so if two or n murderers tries to escape one of them will die, so debiting how is gonna go first and so they will wait. I also belive that we can use math hear, reading the problem i cant stop thinking about concurrency and race conditions. There was a mathmatician called Edward G. Coffman which talked about 4 conditions that have to be present for a interblock to happen. Which are: -1 . Mutual Exclusion -2. Retention and wait. -3 No Explusion: No murderer can be pushed into the door. -4. Circular Wait: You have to wait till the first is fu**k.

[@osasomoregbee4878]

Like a Russian roulette 😂

[@erice.3892]

i have lost so much respect for Blackrock if they actually ask this ridiculous interview question

[@cFoloPL]

You had respect for blackrock?

[@aliasmalias]

@@cFoloPL I expected the question to be if the applicant has any moral and the required answer is no. But an interview question about murder is at least kind of close lol.