Answer: Let X be the amount of money Helen had to start with.
After spending one half of her money on ice cream, she had X - X/2 = X/2 left.
After spending three eighths of her remaining money on soda, she had X/2 - 3X/8 = 5X/8 left.
Since she had $7 left, we have:
5X/8 = 7
X = 56
So, Helen had $56 to start with.
Explanation: