Can you help me with these 3

Which of the fallowing best completes the sequence 5,10,15, a) 30 b) 22 c)25 d)35

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.

Haley buys 9 pounds of apples for $3. how many pounds of apples can she buy for $1?