It is a observation study, because you are observing how much rainfall is in Hawaii at 50 sites.
9^2/9^7
when dividing powers, we subtract the exponents
9^(2-7)
9^ (-5)
a negative exponent flips from the numerator to the denominator
1/ 9^5
Choice D
Answer:
The answer is C/Point E
Step-by-step explanation:
I did the test.
Given:
The sum of two terms of GP is 6 and that of first four terms is 
To find:
The sum of first six terms.
Solution:
We have,


Sum of first n terms of a GP is
...(i)
Putting n=2, we get


...(ii)
Putting n=4, we get



(Using (ii))
Divide both sides by 6.
Taking square root on both sides, we get

Case 1: If r is positive, then using (ii) we get
The sum of first 6 terms is




Case 2: If r is negative, then using (ii) we get
The sum of first 6 terms is




Therefore, the sum of the first six terms is 7.875.