Mindy and Troy combined ate 9 pieces of the wedding cake. Mindy ate 3 pieces of cake and Troy had 1/4 of the total cake. Write an equation to determine how many pieces of cake (c) there were in total. Find the total number of pieces of cake.
c = 9
c = 3 + (1/4)c
Substituting the value of c in the second equation, we get:
9 = 3 + (1/4)c
Subtracting 3 from both sides, we get:
6 = (1/4)c
Multiplying both sides by 4, we get:
24 = c
There were 24 pieces of cake in total. Answer: \boxed{24}.