# Probability theory

• Feb 4th 2008, 08:51 PM
Andreamet
Probability theory
A fair die is rolled six times. If on the nth roll, 1<=n<=6 the result is n, we call it a hit. What is the prob. that we get at least one hit in the six rolls.

Now, do the same but with two dice, and rolling the twelve times. What is the probability that we get at least one hit?
• Feb 4th 2008, 09:06 PM
Ryan J
take the probability of not getting a hit for both. i.e. for the first part it's 1-5/6^6. So, simply take the odds of not getting a hit for the second one. If you cannot figure it out I'll check back in a little while, and solve the second part also.
• Feb 4th 2008, 09:06 PM
mr fantastic
Quote:

Originally Posted by Andreamet
A fair die is rolled six times. If on the nth roll, 1<=n<=6 the result is n, we call it a hit. What is the prob. that we get at least one hit in the six rolls.

Now, do the same but with two dice, and rolling the twelve times. What is the probability that we get at least one hit?

Big hint: In each case, the answer is 1 - Pr(no hits) .......