Final answer:
Debra spent $7 on each comic book.
Step-by-step explanation:
To find out how much Debra pays for each comic book, we need to subtract the amount she spends on sandwiches from the total amount she spent at the store.
Debra bought 6 sandwiches at $2 each, so she spent $12 on sandwiches. Therefore, she spent $54 - $12 = $42 on comic books. Since she bought the same number of comic books each day, she spent $42 / 6 = $7 on each comic book.