To find out how many days Rose needs to spend on vacation to take 11 pictures, we can use the equation provided:
\[ p = 11d \]
We need to solve for \( d \) when \( p = 11 \):
\[ 11 = 11d \]
Now, divide both sides by 11:
\[ d = \frac{11}{11} \] \[ d = 1 \]
Therefore, Rose will need to spend 1 day on vacation to have taken 11 pictures.