You have five cups of bird seed. You use 2/3 cup of bird seed each day. How many days will your bird seed last?

1 answer

you want to convert cups to days.
Since 2/3 cups = 1 day, 2cups = 3days, or 3days/2cups = 1
so, since you can always multiply by 1 without changing things,
5 cups * (3days)/(2cups) = 15/2 days