Peter and Kristin are to read 20 fantasy novels each in a week. Peter can read three times as fast as Kristin. If Peter reads one book in 18 hours, how long will Kristin read half of her books?
How many hours will Kristin take to read one book? ** Since Peter reads three times as fast as Kristin, Kristin will take 18*3 = <<18*3=54>>54 hours to read one book.
How many books does Kristin read? ** Kristin reads half of her books, a total of 20/2 = <<20/2=10>>10 books.
How many hours will Kristin take to read half of her books? ** The time Kristin will take to read half of her books is 10*54 = <<10*54=540>>540
#### 540