Probability Question

[moblongata]

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I was working on the 3rd Topscore Test and couldn't understand the answer to the question:

With one fair die, find the probability of throwing two 4's in 5 tries.

The answer is (10*125)/(36*216)

Anyone have any idea? Thanks so much in advance!

 

[joonkimdds]

I like the puppy.

 

[pbure9]

this is a binomial distribution.

so first you need to find how many possible arrangements of 4's you get get out 5 tries. That's equal to 5C2 which will be 10. So there are 10 possible ways with order not counting to get two 4's in five throws. Next we multiply by the probability of it happening (1/6) and by the probability of it NOT happening (5/6).

The general formula is nCr x (p^r) x (q^n-r) where p is it happening and q is it NOT happening.

So we have 10 x (1/6)^2 x (5/6)^3 = 10*125/6^5 which is the answer

😀 and i like the puppy too

 

[tdkyun]

Probability gets me every time. I'm just going to guess on those.

 

[Doc Smile]

i HATE your stupid bug icon tdkyun. Everytime I read a post i think something is crawling around my screen

 

[192LT192]

HAHAHAHA SAME! i tried to kill it once bc i thought it was on my screen!

 

[dentista123]

I love that Icon!! My bf was sitting next to me and he had to tell me it was fake. Haha

 

[tdkyun]

i HATE your stupid bug icon tdkyun. Everytime I read a post i think something is crawling around my screen

LOL 😍

 

[moblongata]

this is a binomial distribution.

so first you need to find how many possible arrangements of 4's you get get out 5 tries. That's equal to 5C2 which will be 10. So there are 10 possible ways with order not counting to get two 4's in five throws. Next we multiply by the probability of it happening (1/6) and by the probability of it NOT happening (5/6).

The general formula is nCr x (p^r) x (q^n-r) where p is it happening and q is it NOT happening.

So we have 10 x (1/6)^2 x (5/6)^3 = 10*125/6^5 which is the answer

😀 and i like the puppy too

Thanks for the help! I really appreciate it 🙂 🙂
The hockey picture looks cool, too bad I'm not good on skates! 🙁
Hopefully the probability of my understanding of probability has probably increased!

 

[moblongata]

i HATE your stupid bug icon tdkyun. Everytime I read a post i think something is crawling around my screen

I thought I was the ONLY one trying to kill that bug! HA HA! That's was clever...😀