Solving for x: A Narrow Bridge Challenge

[qswdefrg]

Homework Statement

You are crossing a narrow bridge 1km long when you notice a truck approaching at 90km/h. If you can run at 5m/s, how far from the far end must you be if you could reach either end just before being hit by the truck?

My attempt

Displacement between the two: 1000 - x + d
When displacement is 0, they will meet? I can't seem to solve for x... I end up with more variables than I have equations. :S

 

[Borek]

Express the time you need to reach bridge end as a function of x, calculate the time truck needs to reach the end of the bridge. If truck needs more time, you will make it.

Note that there are two answers to the question.