# I cant hack it..

#### koolinoor

##### New Member
A loan application is being processed by a committee of 15 members. Successful application has to be approved by at least 12 members. The probability of a single approval is .7 and it doesn't depend on other members. How big is the probability of loan approval?

#### hlsmith

##### Less is more. Stay pure. Stay poor.
Is this supposed to mean each member's approval probability is 0.7 and each member's decision is independent of the other committee members?

"The probability of a single approval is .7 and it doesn't depend on other members."

#### koolinoor

##### New Member
i've tried the sum of
0,7^12 * 0,3^3
0,7^13 * 0,3^2
0,7^14 * 0,3
0,7^15

#### Dason

##### Ambassador to the humans
You're forgetting the binomial coefficients in front of most of those terms. Have you learned about the binomial distribution?

#### koolinoor

##### New Member
You're forgetting the binomial coefficients in front of most of those terms. Have you learned about the binomial distribution?
nope.. the claim is, that its not required.. what would be your number though?

#### Dason

##### Ambassador to the humans
I'm not doing the problem for you. Have you learned about combinations/permutations?

#### koolinoor

##### New Member
I'm not doing the problem for you. Have you learned about combinations/permutations?
i know about them, yes

#### koolinoor

##### New Member
Well... That's your hint.
that gives me nothing. in any case, i have the end number. and by now, I also have the solution.. in the book, and i give you a hint - it dont include neither of them.
also all this looks a bit hocus-pocus to me. a bit far fetched..

I'm not doing the problem for you. Have you learned about combinations/permutations?
why wouldn't you give me the number? what's your motivation there? in any case, i have it.. i just what to double check, that this thing is real

#### Dason

##### Ambassador to the humans
What exactly do you mean by "I have the number"? Do you have the final probability? Does it include the derivation? You are very vague and like I said I'm not going to do the work for you but I will help you along the way. I've been doing my best to guide you. This problem is trivial to me and I've taught these exact things in many courses before.

So what I'm asking is - tell me what is tripping you up. What exactly do you know. What is causing issue? If you don't want to put in the work and just keep demanding that I 'give you the number' then I'm not doing anything. Best of luck. I want to help but you have to recognize you aren't the one with any power here.

#### koolinoor

##### New Member
Obviously a task in a study book comes with the final answer to check against. I also got the specific algorithm from the professor. And it doesn't include nothing of the things you mentioned: combinations, permutations nor derivations. Nor binomial distribution.

Maybe there are multiple algorithms, that can be applied to get the same result.. i d k.

Whats tripping me, is that I suspect this science is random and the algos are not deterministic by nature.. but more like acupuncture.
Let me put it to your language - the probability of your answer being different than my lecturer is higher than 50%

Am I right?

#### koolinoor

##### New Member
ok.. clearly there are 4 cases, that qualify: 12, 13, 14 or 15 votes.

these probabilities just have to be added. no need for combinations, permutations or derivations

but what is the probability of exactly 12 votes?
is it 0,7^12 * 0,3^3 (inclusive of denials) or just 0,7^12 (non-inclusive of denials) ?

#### Dason

##### Ambassador to the humans
ok.. clearly there are 4 cases, that qualify: 12, 13, 14 or 15 votes.
but what is the probability of exactly 12 votes?
is it 0,7^12 * 0,3^3 (inclusive of denials) or just 0,7^12 (non-inclusive of denials) ?
neither. Once again think about the hint I gave you. Because if you have exactly 12 votes - how many ways are there for that to happen? Think about the definition of combinations (I even narrowed it down for you - you're welcome).

#### Dason

##### Ambassador to the humans
Also I've given so many terms you can google at this point. Search binomial distribution. You might now have learned it but that's no excuse for not searching it and seeing what it's all about. I really don't want to be one of those people that just says rtfm but have you looked through your book? I know there are bad instructors but even bad instructors give external resources (other lectures, books, etc...) to go off of and you can use those. Unless you're in high school (and your profile pic does not suggest that) then it is expected you should be able to get through this. Even with all that said I'm doing my best to help you out - but you need to put in at least *some* effort.

#### koolinoor

##### New Member
neither. Once again think about the hint I gave you. Because if you have exactly 12 votes - how many ways are there for that to happen? Think about the definition of combinations (I even narrowed it down for you - you're welcome).
well, there is but one outcome for 12 votes to happen. whatever combination of members, it still counts as one outcome in the sample space.

my friend, by saying "neither" you have already proven, that your number is different, than the one my lecturer sent me.
so you are wrong and i am right - it is non-deterministic hocus-pocus.

if i understand correctly you want me to solve this problem with binomial distribution, but it is unnecessary, cause why would i trust your algorithm more that an authoritative university professor? mmh? makes no sense right.

#### Dason

##### Ambassador to the humans
Ok. You're speaking gibberish - you don't know the answer and refuse to listen to those that actually do understand probability. Also if you have a single definitive answer to the problem how can you possibly claim that it's non-deterministic hocus-pocus? You're contradicting yourself. Best of luck. I'm done with you.