6 pounds bag for $5.40
1) Considering that an eight lbs bag is $7.2, then we can write out the following:
![(7.2)/(8)=0.9](https://img.qammunity.org/2023/formulas/mathematics/college/yuoj09h81yrsyb0msljvk1qm92yn51mcto.png)
2) So 1 lb of dog food is $0.90. Then examining the options, we can state that the equivalent cost is found at:
![6*0.9=5.40](https://img.qammunity.org/2023/formulas/mathematics/college/yeyerkcgbrsivljco45fef3ls5hfgc5oms.png)
Note that we only had to multiply the number of pounds by the unit ratio.
3) Hence, the answer is
6 pound bag for $5.40