To find the charge \( c \) for a 13-pound package using the formula \( c = 2.03w + 14.24 \), we will substitute \( w = 13 \) into the formula:
\[ c = 2.03(13) + 14.24 \]
First, calculate \( 2.03 \times 13 \):
\[ 2.03 \times 13 = 26.39 \]
Now, add 14.24 to this result:
\[ c = 26.39 + 14.24 = 40.63 \]
Therefore, the cost to send a 13-pound package overnight is $40.63.