Step-by-step explanation:
We can see that this adds by 20, then 100, and so on. Furthermore, it starts at 9, so we can write this as
∑9+20n
The 9 is because we start with 9, and we have a multiplier of 20, so we put the 20 in there as so. On the bottom of the sum notation, we should have n=1 (as when we plug that in, it's our first number) and at the top you can put a variable k as we don't know the maximum. I don't think I can put numbers at the bottom and top of the sum using the tools I have, so that's why I wrote it out
Answer:
D. Population, because it is a collection of salaries for all teachers in the school.
Step-by-step explanation:
In research, population refers to a complete set of subjects that share a characteristic and that the researcher is interested in. On the other hand, a sample is a subset of a population and it's usually the one the researcher takes to make a study with.
In this example, we have "The salary of each teacher in a school" since we are taking ALL the teachers of this school, this would be a population. If we were working with the salary of only a portion of the teachers of said school, it would be a sample.
Thus, the right answer is D. Population, because it is a collection of salaries for all teachers in the school.
Answer:
<u> -54.5%</u>
Step-by-step explanation:
You will have to use this formula
When substituted in you have 
30-66=-36
-36/66= -0.54 (54 repeating)
Then you have to convert this into a percentage, -54.54(repeating) percent
To the nearest hundredth you would round down to<u> -54.5%</u>.
It is a Decrease because it is negatated.
As there are 52 cards in a deck and only 2 types of red cards, the answer would be 2/52 or 1/26
