 
<translate> Grover ga-enweta $0.50 x 20 = $10 maka igbe ọ bụla. Ya mere, ọ ga-enweta $10 x 3 = $30 mgbe o resịrị ihe nkpuchi ihu niile. N'ihi ya, uru nile ọ ga-erite ga-abụ $30 - $15 = $15. Azịza ikpeazụ ya bụ: 15. <eng> Grover will earn $0.50 x 20 = $10 for each box. So, he will earn $10 x 3 = $30 after selling all the face masks. Therefore, his total profit will be $30 - $15 = $15.
The final answer: 15. 