Edited for 4 Colors, 2 faces of the same color case:
You are right Kevin... I calculated that for only 3 colors after, 3 of 4 colors have been selecte
My shot at this (
definately took me more than 2 mins)...
We have 2 triangles and 3 squares.
{2T, 3S} = 5 faces.
Case 1: 3 Colors
Triangles:
Both faces the same color= 3
Both faces different color = 3x2/2 = 3
Total number of distinguishable colors = 6
Squares:
Each face different color = 1 ways
Two faces the same color = 6 ways
Three faces the same color = 3
Total number of ways = 10
Total distinguishable colorings = 10x6 = 60
Case 2: 4 colors
Triangles:
Both faces the same color = 4
Each face a different color = 4x3/2 = 6
Total = 10 ways
Squares:
Each face a different color = 4x3x2/3x2= 4
All faces the same color = 4
For 2 faces of the same color:
# of ways of choosing 3 colors of 4 = 4x3x2/3x2 = 4
For each selected color, # of ways with two faces of the same color = 6
Total ways of having 2 faces with same color = 4x6 = 24
Total = 4+4+24 = 32
Total distinguishable colorings = 10 x 32 = 320
%tage increase = 320 -60/60 = 260/60 = 13/3 = 433%
Therefore r = 433.