To solve for \( p \) in the equation
\[ p - 14.78 = 2.8, \]
you can isolate \( p \) by adding \( 14.78 \) to both sides of the equation:
\[ p = 2.8 + 14.78. \]
Now, perform the addition:
\[ 2.8 + 14.78 = 17.58. \]
So, the solution is
\[ p = 17.58. \]