the pound bag has 25/2 of dog food, or 50/4
if the dog eats 3/4, and the pound has 50/4
[tex]\frac{50}{4} . \frac{4}{3} = \frac{50}{3}[/tex]
if you divide 50 by 3, you'll find 16,66666...
since you need full days, the answer is 16 days
hope it helps :)