Posted by **Lauren** on Thursday, March 29, 2007 at 2:39pm.

I roll 12 4-sided dice. What is the probability that I roll at least one 2? What is the probability that I roll exactly three 2s?

So i take it, on any give roll, the probability of rolling a 2 is .25 (25%); the probability of rolling something else must be .75

The probability of rolling at least one 2 is: one minus the probability of never rolling a two. And, with 12 chances, that probability is .75^12

To calculate the probability of rolling exactly three 2s, first count the numbe of ways can happen. That is, calculate 12-choose-3. This will be (10*11*12)/(1*2*3) = 220. So, the probability of rolling exactly three 2s will be 220*(.75^9)*(.25^3) = 25.8%

## Answer this Question

## Related Questions

- Math - PLEASE - I roll twelve 4-sided dice. What is the probability that I roll ...
- statistic - Roll two 6-sided dice and examine their sum. a) How long will it ...
- statistics - The below table shows the probabilities generated by rolling one ...
- Probability - The newest invention of the 6.041x staff is a three-sided die. On...
- probability - We have two fair three-sided dice, indexed by i=1,2. Each die has ...
- statistics - Roll 2 standard dice and add the numbers. whats the probability of ...
- Algebra 2 - What is the probability when you roll 2 dice and you roll a number ...
- help!!!!! Probability!!! - A fair 6-sided die is rolled twice. The probability ...
- math! - Suppose that to land on Free Parking in the game of Monopoly, you will ...
- math - i'm supposed to make an equation going off of this problem.. it is ...