Abby can buy an 8 pound bag of dog food for $7.40 or a 4 pound bag of the same dog foof for $5.38. whichis the better ?

Okay to do this you have to find the unit rate so that means divide to find how much one is to find out which is the betterr pricce.
    So 7.40/8=0.925 that would be 93 cents for one pound 
5.38/4=1.35 cents for one pound 
So our better deal would be the 8 pound bag even though it cost the most it has the better deal 
    HOPED THAT HELPED

The unit price of an 8 pound bag of dog food for $7.40 is:
$7.40/ 8 pounds= $0.93/pound.

The unit price of a 4 pound bag of dog food for $5.38 is:
$5.38/ 4 pounds= $1.35/pound.

Because $1.35/pound > $0.93/pound, an 8 pound bag of dog food for $7.40 is a better deal.

Hope this helps~