Let's simplify the expression step by step:
Given expression:
\[ 2.2p + 7.7(6.6p + 9.4) - 7.8 \]
First, distribute \(7.7\) into the parentheses:
\[ 7.7(6.6p) + 7.7(9.4) = 50.82p + 72.58 \]
Now substitute this back into the original expression:
\[ 2.2p + 50.82p + 72.58 - 7.8 \]
Combine like terms for the \(p\) terms:
\[ (2.2p + 50.82p) = 53.02p \]
Now, combine the constant terms:
\[ 72.58 - 7.8 = 64.78 \]
Putting it all together, we get:
\[ 53.02p + 64.78 \]
Thus, the simplified expression is:
\[ \boxed{53.02p + 64.78} \]