Answer:
You would expect for 35 people to have consumed alcoholic beverages.
Step-by-step explanation:
For each person, there are only two possible outcomes. Either they consumed alcoholic beverages, or they did not. The probability of a person having consumed alcoholic beverage is independent of any other person. This means that the binomial probability distribution is used to solve this question.
Binomial probability distribution
Probability of exactly x successes on n repeated trials, with p probability.
The expected value of the binomial distribution is:

We learned in Exercise 3.25 that about 70% of 18-20 year olds consumed alcoholic beverages in 2008.
This means that 
We now consider a random sample of fifty 18-20 year olds.
This means that 
How many people would you expect to have consumed alcoholic beverages

You would expect for 35 people to have consumed alcoholic beverages.
X+y+z = 132
x = 7+z
y = 3z
(7+z)+3z+z = 132
5z = 132-7
z = 125/5
z = 25 <=====
x = 7+z
x = 7 + 25
x = 39 <=====
y = 3z
y = 3 × 25
y = 75 <=====
hope it helps :)
1.22 / 1,22
because:
100% of 100 is 100. You multiplied it by one.
110% of 100 is 110. You multiplied it by 1.1 / 1,1
So if you want to multiply by a percentage between 100 and 200 you have to multiply by a number between 1 and 2.
18.75/75=(75/75) -
p =(75-18.5)/75
p=56.5/75
p=0.75(3recurring)