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 travelled 100 km more than the second. The distance between P and Q is : Options
A) 500 km
B) 630 km
C) 900 km
D) 660 km
E) None
Sol.   At the time of meeting, let the distane travelled byb 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 ⇔ x = 400.   So, distance between P and Q = (x+x+100) km = 900 km.   Answer 900 km
<result>C</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 travelled 100 km more than the second. The distance between P and Q is :