Need help with this question. Cannot figure it out.

{I A binary number is a numberthat consists of only the digits 0 or 1. How many distinguishable binary numbers can be formed from the binary number 11001100? Use all of the digits, realizing that the number must begin with 1 in order to use all of the digits. The number of distinguishable binary numbers that can be formed from the binary number 11001100, using all the digits and beginning with 1, is E. (Type a whole number.)