Benny bought along some money when he went on a 3-day trip. On Day 1, he used
1/2 of his money and an additional $100. On Day 2, he used 2/3 of his remaining money.
On Day 3, he used 1/2 of his remaining money and was left with $10. How much money
did he bring to the trip?
(1) $200
(2) $220
(3) $300
(4) $320
