Answer:
Step-by-step explanation:
information given
represent the sample mean
represent the population standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
z would represent the statistic
represent the p value for the test
Hypothesis to test
We want to test if the true mean is less than 12, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
The statistic is given by:
(1)
Replacing the info given we got:
We can replace in formula (1) the info given like this:
It would be c that is the answer
Without any calculations it's evident it can't be neither B (both numbers are even, so they're divisible by 2) nor C (the numbers end in 0 and 5, so they're divisible by 5).
A.

Both numbers have a factor of 3, so they're not relatively prime.
That means it must be D. But, let's check it.

Indeed, those two numbers are relatively prime.