Answer:
After about 22-23 more days Marty will run out of money.
Explanation:
68 divided by 3 is 22.6, so around the mark of 22 days (or 23) he will run out of money. If you need the total amount of days it took to run out of money that would be 36-37, and if you need the total amount of money he had in the beginning that would be $110. I hope this helps! :)