Need Help With this Algebra Question

[Benboy17]

Hi all,
I've been sitting here for about half an hour trying to work this problem out I used to be able to do them quite well but now I can't remember for some reason. No one is around to help me and I really need help please. Here is the question:
An aircraft, used for fire spotting, flies from its base to locate a fire at an unknown distance, x km away. It travels straight to the fire averaging 240km/h for the outward trip and 320km/h for the return trip. If the plane was away for 35 minutes, find the distance, x km.
Got as far as:
240y+320z=.35
Can't find another equation

 

[stapel]

An aircraft, used for fire spotting, flies from its base to locate a fire at an unknown distance, x km away. It travels straight to the fire averaging 240km/h for the outward trip and 320km/h for the return trip. If the plane was away for 35 minutes, find the distance, x km.

Got as far as: 240y+320z=.35

By what reasoning did you arrive at this equation?

Note: Since "y" has units "kilometers", then "240y" has units "(km/hr)*(km) = (km^2)/hr". Does this make sense, in this context? Also, "0.35" means "35%". Since one hour does not have 100 minutes, then "35 minutes" cannot equal 0.35 of an hour.

 

[Benboy17]

Is this homework?

HINT: 240t = 320(35/60 - t) : t = time @ 240

Calculate t, then x = 240t

By the way, 35 minutes does NOT equal .35

Thanks just needed some help to get on the right track haven't done this sort of work in ages