Sorry for posting two threads but I can't seem to figure these out.

1)An express train makes the run between two cities 250km apart in 1.25h less than a local train whose speed is 10km/h less. Find the average speed of the express

2)A farmer has a rectangular field 400m by 500m. On this field a uniform strip on the outside will be left unplanted so that half of the total area will be planted. How wide is the strip?

Thanks so much to whoever took the time to read these