Two trains start from P and Q respectively and travel towards each other at a speed of 50 km/hr and 40 km/hr respectively. By the time they meet, the first train has traveled 100 km more than the second. The distance between P and Q is?
Choose the correct answer:  A) 900 km  B) 300 km  C) 700 km  D) 800 km  E) 100 km
A   900 km   At the time of meeting, let the distance traveled by the second train be x km. Then, distance covered by the first train is (x + 100) km.   x/40 = (x + 100)/50   50x = 40x + 4000 =&gt; x = 400   So, distance between P and Q = (x + x + 100)km = 900 km.
<result>A</result>
Two trains start from P and Q respectively and travel towards each other at a speed of 50 km/hr and 40 km/hr respectively. By the time they meet, the first train has traveled 100 km more than the second. The distance between P and Q is?