Hi!
Suki feeds her dog 0,3 pound of food twice a day, which means that in one day, Suki gives her dog 2 * 0,3 = 0,6 pound of food.
The total amount of dog food Suki bought for her dog is 13,4 pound-bag. To find the number of days the bag of dog food will last, we have to divide the total amount of the bag of dog food, which is 13,4 pounds, by the amount of what Suki gives her dog every day, which is 0,6 pound of food, like this:
13,4/0,6 = (multiply both values with 10) = 134/6 = 22,33
Because it is asked for the number of full days, in this case that's the lower whole number, 22 is the answer.
The bag of dog food will last full 22 days.
Hope this helps!