how would you write a real-world problem that models the following equation

Question

-x + 40 = x
if Alex gained as much money as the lost she would have 40 dollars

Answer 1

Alex originally had a certain amount of money. However, she lost a specific amount of money, and her current balance is equal to the amount of money she had left subtracted from the amount she lost. If Alex were to regain the same amount of money she lost, her balance would be equal to 40 dollars.