13. Amtrak's annual passenger revenue for the years 1990-2010 is modeled approximately by the formula R=-40|x-11|+990 (there is absolute value)
where R is the annual revenue in millions of dollars and x is the number of years since January 1, 1990. In what years was the passenger revenue $790 million?

14. The ideal selling price of a Volkswagen Atlas is $35,000. The dealer allows the price to vary by 5%. What is the lowest price for which this dealer can sell an Atlas? (Your answer must contain an absolute value inequality.)