Directions: Answer the question based on the information given below:

Stella, Tom, and Charlie started their journey at 8 a.m., 9 a.m., and 10 a.m. respectively. The ratio of the speed of Stella, Tom, and Charlie is s: 1.25s: 0.5s respectively. After starting his journey Tom meets Stella after 4 hours. After meeting each other both of them returned to Charlie.