Please Please Please help me with this! Even my math teacher made me fail this!

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

Suppose the equation ||x-a|-b|=2008 has 3 distinct real roots and a not =0. find the value of b.

Amap has a scale of 3.5 inches = 20 kilometers. if the distance between two cities on the map is 4.9 inches, what is the actual distance between the two cities?