ANSWER
-40
Step-by-step explanation
We want to write an integer to represent the situation given:
A debit of $40.
A debit is a situation where money is taken away from an account, as opposed to adding money to the account.
Since money is taken from the account, it means that the amount is subtracted from the account.
In otherwords, we can write that the integer that represents the situation is:
-40