What do we know? : 10 pounds (Cat Food A / C.F.A) = $6.50 20 pounds (Cat Food B / C.F.B) = $14.00
Finding which one is the better deal : If 10 pounds of C.F.A (Cat Food A) is $6.50, if we double the pounds, and cost, we would get 20 pounds of C.F.A for $13.00. This means you can get the same amount of pounds in C.F.A and C.F.B, and costs for 1 dollar less.
(Another way to solve this) : Dividing the cost by pound. C.F.A : 6.50 / 10 = 0.65 So, each pound of Cat Food A equals 0.65 cents.
C.F.B : 14.00 / 20 = 0.7 So each pound of Cat Food B equals 0.70 cents.
Conclusion : In conclusion, both ways can be used to correctly solve this question, and both have the same results. Which is that Cat Food A is the better deal.