Answer:
A.
Step-by-step explanation:
Find a common denominator between the 2 fractions, the common denominator would be 40. So you will Multiple 3/8 by 5/5 giving you 15/40, then you will multiply 1/5 by 8/8 giving you 8/40. Now you can can just add them together which is 23/40. *this answer cannot be simplified*
<h2>
Answer with explanation:</h2>
As per given , we have
Sample size : n= 5
Degree pf freedom = : df= 5-1=4


Significance level for 90% confidence = 
Using t-value table , t-critical value for 90% confidence:

Margin of error of
: 
Interpretation : The repair cost will be within $12.39 of the real population mean value
90% of the time.
Answer:
B.
the complementary angles form a right angle with the shared ray