Michael makes 90% of his free throws in basketball. If he shoots 20 free throws, and if his chance of making each one is independent of the other shots, what is the probability that he makes…
a. all 20?
b. exactly 18?
c. at least 18?

Question

Michael makes 90% of his free throws in basketball. If he shoots 20 free throws, and if his chance of making each one is independent of the other shots, what is the probability that he makes… 
a. 	all 20?
b. 	exactly 18?
c. 	at least 18?

hero · Answer

They must be talking about Michael Jordan

anonymous · Answer

Haha... I think that you missed the point of the question.

anonymous · Answer

Probability make the 20 free throws is
$$
.9^{20} =0.121577
$$

anonymous · Answer

Thank you!!!

anonymous · Answer

Exactly 18
$$
\frac{ 20!}{18! 2!}\,0.9^{18}\,  0.1^2=0.28518
$$

anonymous · Answer

At Least 18
$$
\frac{ 20!}{19!
   1!} 0.1^1 0.9^{19}+
  \frac{
   20!}{18! 2!}0.1^2 0.9^{18}+0.9^{20}=0.676927
$$

anonymous · Answer

Did you understand what I did?

anonymous · Answer

Yeah. Thanks you soo much. I really appreciate it.

anonymous · Answer

yw