Nonstop Train -Math riddle

40.Math Riddles

A nonstop train leaves Moscow for Leningrad at 60 mph. Another nonstop train leaves Leningrad for Moscow at 40 mph. How far apart are the trains 1 hour before they pass each other?

Explanation :  

100 
Two trains speed is 60 and 40 mph. so 1 hour before they will be in a position to cover their speed.
so 60+40 = 100 miles away from each other.