## briitt2k11 Group Title Find the probability. A die is rolled 20 times and the number of twos that come up is tallied. Find the probability of getting exactly five twos. A. 0.129 B. 0.921 C. 0.003 D. 0.083 2 years ago 2 years ago

1. satellite73 Group Title

binomial prob for this one $P(X=k)=\dbinom{n}{k}p^k(1-p)^{n-k}$ in your example $$n=20,k=5,p=\frac{1}{6},1-p=\frac{5}{6}$$

2. satellite73 Group Title

your answer is therefore $\dbinom{20}{5}(\frac{1}{6})^5(\frac{5}{6})^{15}$

3. satellite73 Group Title
4. briitt2k11 Group Title