You can get a hint in the question that it basically asks how much money “DID” I have? This means it is asking about how much YOU had. Not how much you received from anyone. So, the money you had is 18 dollars.
(Since this answers to the question, stating the amount of money you had apart from the money received by you by your parents and relatives.)
Therefore, you had 13 dollars and another 5 dollars originally with you, which sums up to 18 dollars. Clever, right? You have to think outside the box to come up with the answer.
