you have 5 gallons of water you need 1/2 of water to Water Tree then you divide the rest of the word equally among 10 plants how much water does each plant get

This size running track is usually called a 400 meter track. however if a person ran as close to the inside as possible on the track they would run less than 400 meters in one lap. how far away from the inside border would someone have to run to make one lap equal exactly 400 meters