Final answer:
Jonathan could have any negative number less than -$15 in his bank account.
Step-by-step explanation:
In the question, Jessica has -$15 in her bank account. This means that she has a negative balance, indicating that she owes money. The question states that Jonathan has less money than Jessica, so his bank account balance should also be negative. Therefore, one possible value for the amount of money in Jonathan's bank account could be any negative number that is less than -$15. For example, Jonathan could have -$20 or -$30 in his bank account.