The retail price of 12-pack soda can be characterized as having a normal distribution with a mean of 3 dollars and a standard deviation of .25. Below what price do you find 30 % of all 12 packs?

Use z-scores.

Formula:
z = (x - mean)/sd

Use a z-table to find a z-score equating to 30%. Use 3 for the mean and .25 for the standard deviation. Solve the formula for x.

I hope this will help get you started.