If I drive x mph for t hours and then y mph for 2t hours, what is the expression for average speed?

I know the average speed = distance/time but that's where I get stuck.

Printable View

- Jul 24th 2009, 06:14 AMmagentaritaAverage Speed
**If I drive x mph for t hours and then y mph for 2t hours, what is the expression for average speed?**

I know the average speed = distance/time but that's where I get stuck.

- Jul 24th 2009, 06:47 AMmathaddict
- Jul 24th 2009, 06:48 AMCaptainBlack
- Jul 24th 2009, 06:49 AMsongoku
- Jul 24th 2009, 06:49 AMyeongil
Or... d = rt.

If you drive x mph for t hours, then the distance traveled is xt miles.

If you drive y mph to 2t hours, then the distance traveled is 2yt miles.

Total distance: xt + 2yt.

Total time: t + 2t = 3t.

Average speed:

$\displaystyle \frac{xt + 2yt}{3t} = \frac{x + 2y}{3}$

01

Edit: beaten to it by**three**people! (Rofl) - Jul 24th 2009, 06:53 AMsongoku
- Jul 24th 2009, 12:36 PMmagentaritaThanks..
I want to thank all of you.