Please answer the following question by reasoning step-by-step.
Julia has $40. She spends half of her money to buy a new game for her phone. She spends a quarter of what she has left on in-game purchases. How much money does she have left?

15
Julia spend $40 / 2 = $20 on the game.

After buying the game, she has $40 - $20 = $20 left.

She spent $20 / 4 = $5 on in - game purchases.

She has $20 - $5 = $15 left.

.

The final answer: 15