ECON 102 please help! Someone who is in microeconomics need help. Please provide a thorough and detailed answer to the question please

Economists believe that people think "on the margin". On the margin means: increasing, by small amounts, whatever you are doing right now. For example, if you are currently driving the speed limit (65 mph), you have a choice to go, say, 70 mph. In making this decision as to whether you should drive faster, what are the extra benefits and costs from going 70 instead of 65