How many miles will 20 litres of petrol get me?

I have a Ford KA 1.2 don't know the MPG at all. But I know I have half a tank of petrol which is 20 Litres and I need to do about a 90 Mile trip, wondering if'll get me there.

Added (1). I'm going to be driving on A Roads, instead of the motorway.

It will easily do that and some more on that fuel

What is the problem? In a 90 mile trip you're bound to pass a filling station or two, when your fuel gauge gets to quarter full pull into the next one and fill up again.

Hi yes provided it is not an old car with loads of rubbish in the bottom of the fuel tank. Suck any of that up and get an expensive repair bill.

It will definitely get you there.

http://www.carpages.co.uk/guide/ford/ford-ka-edge-1.2.asp
Since the KA is a UK automobile you could mention things in kilometres.
Urban Fuel 48.7 mpg
Extra Urban 64.2 mpg
Combined 57.7 mpg
Fuel Capacity 35 litres

Now, if you have about half a tank, let's assume 18 liters instead of 20.
In a road trip, it should be mostly highway miles (Extra Urban) so let's use 60 miles per gallon.
You have 4.75 gallons of petrol (gasoline).
It should be good for about 285 miles (458 km).
You should have no issue at all.

To be precise we would need to know the exact road conditions of your journey - but you should get at least 40 mpg - and as you have over 4 gallons of fuel you are going to be OK for 150 miles or more.

Up to 57.7 MPG
http://www.ford.co.uk/Cars/Ka/Performance-and-efficiency

depends on the state of the engine and how you drive it though, might only get 30 if it's rough and you drive it like you stole it.

20 liters = 4.39938 gallons