Mr zambito buys a 3 1/2 - pound bag of dog food every 3 weeks mr zambito feeds his dog the same amount of dog food each day how many pounds of dog food does his dog eat each year show your work

3 1/2 pound = 7/2 pounds.
We know that the dog eats 7/2 (3.5) pounds every 21 days since there are 7 days in a week and Mr.Z only buys dog food every 3 weeks.

Set up a proportion.     3.5 lb     =        x     
                                 21 days         365 days

Cross multiply and divide. 3.5 lb x 365 days = 1277.5 / 21 days = 60.83 lb

Ait gives no info about the y at the end therefore it has no solution