Alex spent 25% of his money on a sports drink. Then he spent 25% of the remaining money on trail mix. He has $9 left. How much money did Alex begin with?
If Alex has spent two lots of 25%, this is equal to 50%, which means he has spent half of his money. If he has $9 left, this means that he has spent $9, meaning that he started with $18. Hope this helps :)