Convert to a base 10 integer, where the 'digits' A through F represent the values 10, 11, 12, 13, 14, and 15 in order.
This question does not make sense. you have not said what base it is in now.
I suspect what you mean is
Convert THIS base 10 integer to BASE 16 , where the 'digits' A through F represent the values 10, 11, 12, 13, 14, and 15 in order.
in which case the answer will be
A,B,C,D,E,F
OR .... Maybe it is the actual number that you wanted converted that you have failed to include?