Step-by-step explanation:
180° = m<A + m<B + m<C
180° = 45° +60° + m<C
180° = 105° + m<C
m<C = 180° - 105 °
m<C = 75°
I really don't know how toowrk it out on paper, I'm afraid. I just looked at it, and somehow knew that the answers are 7 and 9.
Answer:
We need to conduct a hypothesis in order to determine if the mean is greater than specified value, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
For this case the significance is 1%. So we need to find a critical value in the normal standard distribution who accumulates 0.99 of the area in the left and 0.01 in the right and for this case this critical value is:

Step-by-step explanation:
Notation
represent the sample mean
represent the standard deviation for the population
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
z would represent the statistic (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to determine if the mean is greater than specified value, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
For this case the significance is 1%. So we need to find a critical value in the normal standard distribution who accumulates 0.99 of the area in the left and 0.01 in the right and for this case this critical value is:

Y = 30/20x + 20
( i haven’t done this in a while but i’m pretty sure this is right)