Sos with this question( if you could explain how you got it that would be great too)

The lengths of nails produced in a factory are normally distributed with a mean of 4.91 centimeters and a standard deviation of 0.05 centimeters. find the two lengths that separate the top 4% and the bottom 4%. these lengths could serve as limits used to identify which nails should be rejected. round your answer to the nearest hundredth, if necessary.

How do i put 3(x+7) in distributive property

Will give a: 122 b: 90 c: 48 d: 180