Question

from a base elevation of 9500 ft., a mountain rises to a summit elevation of 14318 ft. over a horizontal distance of 15847 ft.

would the grade of the peak be 3.3%

Answer 1

If grade is defined as rise over run expressed as a percent, then:
the rise is:
summit - base = 14318 - 9500
the run is the horizontal distance = 15847.
Using these definitions, the grade is not 3.3%