The U.S. Fish and Wildlife Service reported that the mean length of six-year-old rainbow trout in the Arolik River in Alaska is 481 millimeters with a standard deviation of 41 millimeters. Assume these lengths are normally distributed.

a. Find the 58th percentile of the lengths.

b. Find the 76th percentile of the lengths.

c. Find the first quartile of the lengths.

d. A size limit is to be put on trout that are caught. What should the size limit be so that 15% of six-year-old trout have lengths shorter than the limit?