Please help Me answer A B and C

I will give brainlst :)!

Asimple random sample of size nequals14 is drawn from a population that is normally distributed. the sample mean is found to be x overbar equals 70 and the sample standard deviation is found to be sequals13. construct a 90% confidence interval about the population mean

41/17 as a decimal rounded to the nearest hundredth

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?