Answer:
Step-by-step explanation:
Given that
Population mean 
std deviation
= 12
sample size n =36
Sample mean = 

(Two tailed test)
Mean difference = 7
Std error =
Since population std dev is known and n>30 we use Z test
Z statistic = 
p value <0.001
Since p value is <0.01, at 1% significance level, we reject H0.
There is significant difference between sample mean and population mean.
Answer: r=14
Step-by-step explanation:
because they are vertical angles
7r+6=8r-8
solving for r you get
r=14
Answer:
40
Step-by-step explanation:
it's 8+8+8+7+9 so it's gonna be 40