I have a question here I've been trying to solve to no avail for about a week:

If terry hiked 0.5km/h faster, he would take 1 hour less to complete a 15 hour hike. What was his hiking speed?

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I'm under the impression I use the formula T=D/S, but that's where my problem comes in, I have no idea what the distance is, so the farthest I get is this:

15-1=14 (faster speed time)

14 = *blank*/x+0.5
15 = *blank*/x

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I'm not looking for the end answer, I would just like a little help with how I'm supposed to set up my equations to solve it.

The distance is .

The trip normally takes 15 hours hiking at rate 'r'.

But, it only takes 14 hours hiking at rate 'r+1/2'.

The distance is still the same.

So, we have



Solve for r.