Amy's least favorite weekly chore is mowing the lawn, even though it only takes her about 30 minutes. Her family's lawn is 1,000 square yards, but her parents are thinking about moving to the country, where they would have 5 acres of land. If the time it takes Amy to mow a lawn is proportional to its area, how many hours would it take her to mow 5 acres?
Hint: There are 4,840 square yards in 1 acre.