Bobby likes to hike the trails near his house. On Saturday, he spent 4 hours hiking 8 miles. On Sunday, he plans to hike 12 miles.
If he hikes at the same rate, how many hours will he spend hiking on Sunday?
On Saturday, Bobby hiked at a rate of 8 miles / 4 hours = <<8/4=2>>2 miles per hour.
Therefore, on Sunday, he would hike for 12 miles / 2 miles per hour = <<12/2=6>>6 hours. Answer: \boxed{6}.