To find out how much wrapping paper Bryan used for each doll, you can divide the total amount of wrapping paper he used by the number of dolls.
He used \( \frac{7}{8} \) of a roll of wrapping paper for 3 dolls.
To find the amount of paper used for each doll:
\[ \text{Amount of paper per doll} = \frac{\frac{7}{8}}{3} = \frac{7}{8} \times \frac{1}{3} = \frac{7}{24} \]
Thus, Bryan used \( \frac{7}{24} \) of a roll of wrapping paper for each doll.