Need help with a word problem

An airplane travels at an unknown elevation before it descends 3 miles to an elevation of 15 miles. find the elevation of the plane before its descen.

If your score on your next statistics test is converted to a z score, which of these z scores would you prefer: minus2.00, minus1.00, 0, 1.00, 2.00? why? a. the z score of 2.00 is most preferable because it is 2.00 standard deviations above the mean and would correspond to the highest of the five different possible test scores. b. the z score of 0 is most preferable because it corresponds to a test score equal to the mean. c. the z score of minus2.00 is most preferable because it is 2.00 standard deviations below the mean and would correspond to the highest of the five different possible test scores. d. the z score of minus1.00 is most preferable because it is 1.00 standard deviation below the mean and would correspond to an above average

Evan walked 5/8 mile to his friends house.then together they walked 7/12 mile to the movie theatre.which pair of fraction can evan use to find how far he walked in all?