Question 939420
mean 70 and standard deviation of 15
{{{z = blue(X - mu)/blue(sigma)}}} 
15invNorm(.95) + 70 = Xa = 95, cut off for A
15invNorm( .70) + 70 = Xb = 78 cut off for B   
15invNorm(.10) + 70 = Xc = 51 cut off for C