What is the additive inverse of 0?

How to do this , and can some one explain

Kyle and elijah are planning a road trip to california. their car travels 3/4 of a mile per min if they did not stop driving, how many miles could kyle and elijah drive in a whole day? ? 1 day = 24 hours. plzzz i will give you 100 points

Your friend uses c=50p to find the total cost, c, for the people, p, entering a local amusement park what is the unit rate and what does it represent in the context of the situation?