Choose the correct scale factor:

Pls help

Identify a1 and r for the geometric sequence an= -256(-1/4) n-1

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.

This is so hard and it’s for a test