Environmental math and science problem, please help and explain process if you can. Thank you so much!

7. Here are two pieces of information: President Trump's administration has moved to freeze increasing standards for vehicle fuel efficiency. President Obama's administration had raised the fleet-averaged fuel efficiency standard for US cars and light trucks to ~50 miles per gallon for 2025. Today's fleet (which averaged ~25 miles per gallon in 2017) consumes about 130 billion gallons of gasoline each year. Reversing another Obama administration decision, President Trump has also taken actions to enable greater flow of crude oil from the Canadian tar sands to refineries in the U.S. The flow of oil in the proposed Keystone XL pipeline would be about 800,000 barrels per day. A barrel of tar sands oil yields about 20 gallons of gasoline. a) Compare the amount of fuel obtained annually from the pipeline, if it is built, with the amount saved annually by maintaining President Obama's fuel efficiency standard. (10 pts.) b) List 3 big-picture factors or issues that this simple comparison ignores. (6 pts.) 7. Here are two pieces of information: President Trump's administration has moved to freeze increasing standards for vehicle fuel efficiency. President Obama's administration had raised the fleet-averaged fuel efficiency standard for US cars and light trucks to ~50 miles per gallon for 2025. Today's fleet (which averaged ~25 miles per gallon in 2017) consumes about 130 billion gallons of gasoline each year. Reversing another Obama administration decision, President Trump has also taken actions to enable greater flow of crude oil from the Canadian tar sands to refineries in the U.S. The flow of oil in the proposed Keystone XL pipeline would be about 800,000 barrels per day. A barrel of tar sands oil yields about 20 gallons of gasoline. a) Compare the amount of fuel obtained annually from the pipeline, if it is built, with the amount saved annually by maintaining President Obama's fuel efficiency standard. (10 pts.) b) List 3 big-picture factors or issues that this simple comparison ignores. (6 pts.)