Answer:
a
b
Step-by-step explanation:
From the question we are told that
The mean is 
The standard deviation is 
Generally 2 year is equal to 24 months
Generally the percentage of total production will the company expect to replace is mathematically represented as

Generally 

Generally from the z-table

So

Converting to percentage

=>
Generally the duration that should be the guarantee period if Accrotime does not want to make refunds on more than 6% is mathematically evaluated as

=> 
From the normal distribution table the z-score for 0.06 at the lower tail is

So

=>
Answer:
He can apply for 4 different majors at each college giving
5 * 4 = 20 (if the college permits more than 1 application for a major)
Answer:
10/13 = 76.92%
Step-by-step explanation:
The question is missing some information because the underline is missing.
If we make table based on if the letter upper case (A) or lower case(a), and if the letter underlined(B) vs not underlined(b) the data will be:
A a
B 4 3 7
b 3 3 6
total 7 6
There are total of 13 letter there. The calculation will be:
P(A or B) = P(A) + P (B) - P(A and B) = (7 + 7 -4) / 13= 10/13 = 76.92%