Pretty simple equation, where we need to find the number of books. If it is 2$ each day per book
72/9 = 8$ per day is the late fee paid
So if each book is 2$, then we can assume
8/2 = 4 books
So equation is
“# books = (amount paid)/(days * per day payment)”
Answer: a. n= 1068
b. n= 164
Step-by-step explanation:
The formula to find the sample size :

, where p=prior population proportion , z* = critical z-value and E = Margin of error.
Here , let p=proportion of computers that use a new operating system.
Given : Confidence level = 95%
i.e. z* = 1.96 [by z-table]
Margin of error : E = 3% =0.03
a. If p is unknown , then we assume p=0.5
Then, 
i.e. n= 1068
b. p=0.96
Then, 
i.e. n= 164.
Answer:
Step-by-step explanation:
To make the problem easier to solve, we will set it up as the equation of the length of time of each class times the number of classes equals the total amount of minutes. However, since we don't know the number of classes, we'll symbolize our two unknowns with two variables.
75x + 45y = 705
(75x + 45y)/15 = 705/15
5x + 3y = 47
y = (47-5x)/3
It looks like we can't simplify the equation any more, so now it is a matter of trial and error. The minimum number of Saturday classes means the maximum number of weekday classes. We first will test for the maximum by assuming there are no Saturday classes, then will work our way up until x is an integer.
If x = 0
(47-5(0))/3 = 47/3 = 15.6666
If x = 1
(47-5(1))/3 = 42/3 = 14
This works. Therefore, the maximum number of weekday classes is 14, or choice b.
One way of estimating is to Round the numbers to the nearest whole number.
Hope this helps!