80 * 5/8 will give you how many are thoroughbreds.
80 * 5/8 = 50
Now subtract this from all of the horses.
80 - 50 = 30.
There are 30 quarter horses.
OR If 5/8 of the horses are thoroughbreds, then 3/8 are quarter horses.
80 * 3/8 = 30.
Answer:
I'm pretty sure it's B.20%
Answer:
11.44% probability that exactly 12 members of the sample received a pneumococcal vaccination.
Step-by-step explanation:
For each adult, there are only two possible outcomes. Either they received a pneumococcal vaccination, or they did not. The probability of an adult receiving a pneumococcal vaccination is independent of other adults. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
70% of U.S. adults aged 65 and over have ever received a pneumococcal vaccination.
This means that 
20 adults
This means that 
Determine the probability that exactly 12 members of the sample received a pneumococcal vaccination.
This is P(X = 12).


11.44% probability that exactly 12 members of the sample received a pneumococcal vaccination.