<span>From the message you sent me:
when you breathe normally, about 12 % of the air of your lungs is replaced with each breath. how much of the original 500 ml remains after 50 breaths
If you think of number of breaths that you take as a time measurement, you can model the amount of air from the first breath you take left in your lungs with the recursive function

Why does this work? Initially, you start with 500 mL of air that you breathe in, so

. After the second breath, you have 12% of the original air left in your lungs, or

. After the third breath, you have

, and so on.
You can find the amount of original air left in your lungs after

breaths by solving for

explicitly. This isn't too hard:

and so on. The pattern is such that you arrive at

and so the amount of air remaining after

breaths is

which is a very small number close to zero.</span>
Answer:
9 . (4)
10 . 17
Step-by-step explanation:
Answer:
Here the sample is the college students, and the researcher want's to do a survey to obtain information about marriage patterns.
Then, the ideal sample will be constituted of students of both genders, of different ideologies, of different social classes, of different religions, etc.
Then the thing that the researcher needs to do is:
Define the size of the sample
Assign to each student a unique number.
using a random number generator, generate enough different numbers to fill the sample.
Each of these numbers corresponds to a unique student, so now you have a complete sample of random selected students.
This sample can not be biased in any way.