# Math Help - Probability- result of multiple trials

1. ## Probability- result of multiple trials

Lets say that there is a 30% chance for me to obtain a certain item when i kill something.

Now lets say that I kill it again. Chances remain the same however, I'm confused on how to calculate the probability that I'm going to obtain that one object out of those two trials

Basically, if i were to perform a task with a 30% chance to win the gold every time. What is the overall chance that I might win one object out of those 10 trials, or 2 objects out of those 10 trials.

I couldn't find an answer as I surfed the web

Sorry if this question is confusing, or if its stupid and simple.

Thank you!!

2. Originally Posted by KhangesKhan
Lets say that there is a 30% chance for me to obtain a certain item when i kill something.

Now lets say that I kill it again. Chances remain the same however, I'm confused on how to calculate the probability that I'm going to obtain that one object out of those two trials

Basically, if i were to perform a task with a 30% chance to win the gold every time. What is the overall chance that I might win one object out of those 10 trials, or 2 objects out of those 10 trials.

I couldn't find an answer as I surfed the web

Sorry if this question is confusing, or if its stupid and simple.

Thank you!!
Binomial distribution - Wikipedia, the free encyclopedia

3. If I have interpreted the question correctly, you want to know the probability of "getting the gold" once and twice in 10 chances.

Getting the gold once:

If we want to get the gold exactly once, we multiply:

$\displaystyle \frac{3}{10}*(\frac{7}{10})^9$ I'm only multiplying by 3/10 once because we want the gold exactly once.

This gold can be obtained in any of the 10 different chances. Therefore, we must multiply the expression above by 10 to find the probability of getting the gold once.

Getting the gold twice:

If we want to get the gold twice, we multiply as such:

$\displaystyle (\frac{3}{10})^2*(\frac{7}{10})^8$

We can get a combination of two golds in any of 10 choose 2 ways. Therefore, we multiply the expression above by 10 choose 2, and we have the probability of getting the gold twice.