Well this only simplifies to a smaller equation
so the answer would be...
2a²-9b²
Answer:
So then the correct answer would be:
B) .9996
Step-by-step explanation:
The exact way to solve this problem is using the binomial distribution, assuming that our random variable of interest is "number of students living in apartments" represented by X and 
And we want this probability:
So we see that we satisfy the conditions and then we can apply the approximation.
If we appply the approximation the new mean and standard deviation are:
And then 
And we are interested on the following probability:
So then the correct answer would be:
B) .9996