Lizzy: Lucy lost one-third of her money. She then spent one-fourth of the remainder, and only left with $15. How much money did Lucy have at the beginning?.
Me: Hmmm, let me think. I think this is the detailed solution:
The $15 is 1 - 1 / 4 = 3 / 4 of the money left. Since 3 / 4 is equal to $15, then 1 / 4 is equal to $15 / 3 = $5. So Lucy had $5 x 4 = $20 left after losing 1 / 3 of her money. Hence, $20 is 1 - 1 / 3 = 2 / 3 of the money that Lucy had at the beginning. Since 2 / 3 is equal to $20, then 1 / 3 is equal to $20 / 2 = $10. Therefore, Lucy had $10 x 3 = $30 at the beginning. Final answer: 30.