I think the answer is b i've never learned this sorry :(
Every confidence interval has associated z value. As confidence interval increases so do the z value associated with it.
The confidence interval can be calculated using following formula:

Where

is the mean value, z is the associated z value, s is the standard deviation and n is the number of samples.
We know that standard deviation is simply a square root of variance:

The confidence interval of 95% has associated z value of <span>1.960.
</span>Now we can calculate the confidence interval for our income:
The answer in is 4.4 bc 1/3 of 13.1(which is half of the total distance) is 4.4
Since, population of species A is represented by : 
Let us find the population of species A, at the end of week 1:
i.e., x = 1
i.e., 
i.e., 
i.e., 
Also, since population of species B is represented by : 
Let us find the population of species B, at the end of week 1:
i.e., x = 1
i.e., 
i.e., 
i.e., 
Thus, at the end of 1 week, species A and species B will have the same population.
Hence, option D is correct.
12h-9h=3h move everything else to other side
3h=20-40+6
3h=-14
divide by 3
h=-14/3