The first one is A and the second one is B, hope this helps!!
Answer:
For a sample size of 10, the t-value is about 3.25 (from tables) at a 99% confidence interval.
Explanation:
When the standard deviation for the population is not known, the confidence interval estimate for the population mean is performed with the Student's t-distribution.
The confidence interval for the mean is calculated as

where

= sample mean,
s = sample standard deviation,
t = t-value (provided in tables),
n = sample size.
When reading the t-value, (n-1) is called the df or degrees of freedom.
The answer is (-7r-6s)/3s
Move the decimal point to the right one place value.
1.7 x 10 = 17
17 is your answer
hope this helps