Answer:
8 hours.
Explanation:
The pizza house will pay 10 - 6 = 4 dollars in late charges. Each hour costs them 1 dollar. (0.25 per 1/2 hour 0.50 dollars for 1 hour.)
So 1 hour gives a reduction of 0.50 dollars.
x hours gives a reduction of 4 dollars.
0.50 x = 4.00 dollars.
x = 4/0.50
x = 8 hours.
If they keep that up, they will be out of business before too long.