Answer:
Distance cannot be negative because no matter which direction you travel, you will never travel negative units.
Explanation:
Distance cannot be negative in the same way that when you put a car in reverse, the odometer does not go backwards.
If you have a mailbox 30 feet east of your house and a park 30 feet west of your house, you can think of it like a number line: your house is 0, the park is -30 and the mailbox is 30. But, if you walk to your park, you have not walked -30 feet.