Binomial Distribution

[dreamer2415]

Here is the problem:
given a binomial random variable with n=10 and p=.3, use the formula to find the following probabilities
a. P(X=3)
b. P(X=5)
c. P(X=8)

I know the answers to the ? (a. .2668 b. .1029 c. .0014) but i cant figure out how you get the answer.
Thank you in advance

 

[galactus]

Plug them into the formula:

\(\displaystyle P(X=k)=\binom{n}{k}(p)^{k}(1-p)^{n-k}\)

P(X=3):

\(\displaystyle \binom{10}{3}(.3)^{3}(.7)^{7}\)