If you would like to know for how many days will 1/2 of a bag of dog food last, you can calculate this using the following steps:
1 day ... 3 bags of dog food
x days = ? ... 1/2 of a bag of dog food
1 * 1/2 = 3 * x
1/2 = 3 * x /3
x = 1/2 * 1/3
x = 1/6 of a day
The correct result would be 1/6 of a day.
