On a trip from the United States to Canada, Isabella took U.S. dollars. At the border she exchanged them all, receiving 10 Canadian dollars for every 7 U.S. dollars. After spending 60 Canadian dollars, she had Canadian dollars left. What is the sum of the digits of ?
This problem is copyrighted by the American Mathematics Competitions.
Instructions for entering answers:
For questions or comments, please email email@example.com.