Car race riddle (not too hard, not too easy)

[Couperin]

My mum told me this one, it's pretty cool :).

The red car and the blue car are having a race. The red car, which has a top speed of 70mph has a 20 minute head start over the blue car, which has a top speed of 80mph.

Assuming that top speeds are reached the very instant a car starts, and that the top speeds are constant, how long will it take, in minutes, for the blue car to catch up with the red car?

 

[cristo]

This isn't really a brain teaser.. its a simple physics problem...

 

[Couperin]

Okay I'll add another element. When the blue car finally catches up with the red car, the driver of the blue car looks through the window and notices that the driver of the red car has a dagger through his chest. On the passenger side seat sits a dog wearing a Sherlock Holmes hat, who woofs twice. There is also a small puddle of cool water in the front footwell. How did the driver of the red car die?

Anyway sorry I didn't realize that this wasn't the place for this kind of problem :D.

 

[Feldoh]

Okay I'll add another element. When the blue car finally catches up with the red car, the driver of the blue car looks through the window and notices that the driver of the red car has a dagger through his chest. On the passenger side seat sits a dog wearing a Sherlock Holmes hat, who woofs twice. There is also a small puddle of cool water in the front footwell. How did the driver of the red car die?

Lol...