At Least Once Probabiility

Question

Henry is a basketball player, and the probability that he makes any given free throw is about 70%. What is the probability that he will make one or more of his next 4 free throws?

_____%. (Round to the nearest tenth of a percent.)

Answer 1

If there is a 30% probability of someone missing a show, what is the probability that they miss four shots in a row?

Sometimes you can calculate the probability that something doesn't happen easier than you can the probability that something does happen. Remember that if you add the probabilities up their sum will be 1.

Answer 2

.7 is the odds of making the first free throw

 

.3 is the odds of missing the first

 

in two throws the odds are

 

.7 +.3(.7)

 

in three throws

 

.7+.3(.7)+.3(.3)(.7)

 

in four

 

T=.7+.3(.7)+.3(.3)(.7)+.3(.3)(.3)(.7)

=.99

 

an easier way to solve this is to consider the chance that he missed all four

 

m=.3(.3)(.3)(.3)=.0081

 

this the opposite so

1-m=.99