Captain Black, he said that he knew that "using a calculator" and asked how you would find it "by hand".
Jimmy W, if (mod 10752) then 55d= 10752k+ 1 for some integer k. That is the same as 55d- 10752k= 1 so, using Euclid's algorithm:
55 divides into 10752 195 times with remainder 27. 27 divides into 55 twice with remainder 1. That is: 55 -2(27)= 1 and, since 10752- 195(55), that is 55- 2(10752- 195(55))= (1+ 2(195))(55)- 2(10752)= 391(55)- 2(10752)= 1. That means that one solution is d= 391, k= 2.