Hello! There is this problem that I have stumbled upon, but I can't seem to wrap my head around it or remember the approach you need to take for it. Overall, I struggle to solve it. The problem goes as follows: 

Jack can unload the truck twice as fast as Shaun can. Together they can unload the truck in 5 hours. How long would it take each of them working alone to unload the truck?

You can just direct me to the appropriate video explaining a similar problem, that will suffice.