Adam starts from a point P towards North at a certain time and after sometime Bohr also starts from P towards North and catches up with Adam at 12:00 noon. Had Bohr started an hour later, he would have caught up with Adam at 4:00 p.m. What is the ratio of the speeds of Adam and Bohr?

1) 4:5
2) 3:4
3) 2:3
4) 1:4