A tour guide at a museum was showing a group of tourists around. He brought the group to an exhibit of the complete skeletal remains of a dinosaur. He said to the group "This dinosaur is 100million and 8 years old". The group was impressed, and one asked "Wow, how can the palaeontologists be so accurate?" The tour guide replied..."Easy. When I first started here, I was told it was 100million years old. And I have been working here for 8 years..."