2 trains, Express and Commuter, leave the station at the same time. Express, which heads north travels 10km per hour faster than Commuter, which goes east. If the trains are 100 km apart after 2 hrs, find the speed of each train.
I thought the equation would be a^2 + b^2 = c^2, or (x+20)^2 + x^2 = 100^2 but I can't get the math to work, so I think something must be wrong with this logic. Can you help?

Question

2 trains, Express and Commuter, leave the station at the same time. Express, which heads north travels 10km per hour faster than Commuter, which goes east. If the trains are 100 km apart after 2 hrs, find the speed of each train. 
I thought the equation would be a^2 + b^2 = c^2, or (x+20)^2 + x^2 = 100^2 but I can't get the math to work, so I think something must be wrong with this logic. Can you help?

anonymous · Answer

ex=com+10
ex/2+com/2=100 try this

anonymous · Answer

Doesn't direction factor in?

anonymous · Answer

i guessed :S

anonymous · Answer

solve $$100^2 = (2x+20)^2+(2x)^2$$

anonymous · Answer

That is what I finally figured out, thanks!