Question 622224
Draw out the picture. It's always a good idea to draw out the picture (as accurately as you can) even if you have no idea what to do or where to go.
A drawing may help you see what you have to do.


<img src="http://i150.photobucket.com/albums/s91/jim_thompson5910/Algebra%20dot%20com/6-20-201212-28-47AM.png">


Our goal is to find h. But to do that, we need to find w. We can use the tangent function to say that


tan(70) = opp/adj


tan(70) = h/w


Then solve for w to get 


w = h/tan(70)


w = h/2.747477


w = 0.36397h


Now we can say 


tan(40) = h/(x+w)


tan(40) = h/(24+w)   ... Note: x = 24 as it's given that the two stations are 24 km apart.


tan(40) = h/(24+0.36397h)


From here, you can solve for h (since that's the only variable left). I'll let you do this.