Answer: The 4.2 kilograms bag
Step-by-step explanation: First of all, the average month has 30 days, so we want to make sure that Paige can feed her dog for at least a month, or 30 days.
First, multiply the amount Paige will feed her dog per day, 0.12 kilograms by 30 to see the total amount of kilograms she will need to feed her dog.
0.12 x 30 = 3.6 kilograms. So, Paige will need 3.6 kilograms to feed her dog for a month.
So, Paige will need to buy at least the 4.2 kilogram bag in order to feed her dog for a month because the other two bags don't have enough food. Paige will even have some food left over for a couple of extra days.