Shannon,

In this problem, for the equation z = (x - u)/s, you are given x=2.0 and x=0.75.

So, z = (2.0 - u)/s and z = (0.75 - u)/s

You are also told that 2.0 or above contains 16.6% of the normal curve, and 0.75 or below contains 6.68% of the normal curve. Look up the z values for each of those proportions (hint - 16.6% in the upper tail, and 6.68% in the lower tail) and plug them into the equations above.

Now you'll have two equations with two unknowns (u and s). Using a little algebra to solve two equations with two unknowns will get you to the answers for u and s.

Hint: for the two equations, set them up like this-

z = (x - u)/s ---> u = x - (z*s)

Let us know if you get stuck again.

John