The answer is probably:
BB = Blue
Bb = Blue
RR = Red
Rr = Red
BR = Blue and Red
BBRR = Blue and Red
BbRr = Blue and Red
bbrr = Blue and Red
Each letter represents a color
The capital letter is dominant over the uncapitalized letter
BR means there is 50% for each color
Br means 100% blue
Good Luck!