So, we know that:

We also know that
. We will use that fact to find
in terms of
and
.

Therefore:

Answer:
The answer to your question is 43.8 mL of acid.
Step-by-step explanation:
Data
Total volume = 362 ml
12.1 % is acid
The Volume of acid = ?
Process
1.- Use the rule of three and cross multiplication to solve this problem.
362 ml ------------------- 100%
x ------------------- 12.1 %
x = (12.1 x 362) / 100
x = 4380.2 / 100
x = 43.802 ml
2.- Round your answer to the nearest tenth.
43.802 only consider the first decimal
43.8 mL
3.- Conclusion
A 12.1% solution of acid has 43.8 mL of acid.
Answer: 
Step-by-step explanation:
The confidence interval estimate for the population mean is given by :-
, where
is the sample mean and ME is the margin of error.
Given : Sample mean: 
The margin of error for a 98% confidence interval estimate for the population mean using the Student's t-distribution : 
Now, the confidence interval estimate for the population mean will be :-

Hence, the 98% confidence interval estimate for the population mean using the Student's t-distribution = 