Can someone please help me I will mark u brillant

Given the following sampling distribution of one mean with a sample size 49, from a normally distributed population,find the population standard deviation, o.79828588912497

Sally deposited money into a savings account paying 4% simple interest per year.the first year,she earned $75 in interest.how much interest will she earn during the following year?

21/2 divided by 3 1/3 = s divided by 4 1/4 . what is s?