We need to calculate the value of the following expression:
\[
\sqrt{13824} + \sqrt{15625}
\]
### Step 1: Simplify the square roots
- \( \sqrt{13824} = 6 \) (as \( 6^2 = 13824 \))
- \( \sqrt{15625} = 7 \) (as \( 7^2 = 15625 \))
### Step 2: Add the results
Now add the two values:
\[
6 + 7 = 13
\]
Thus, the correct value is \( \boxed{7} \).