Multiple choice

Two trains start simultaneously from two stations $300$ km apart and move towards each other.The speed of one train is more than the other by $20$ km/hr. If the distance between the trains after two hours is $20$ km, find the speeds of the trains.

  1. Speed of the first train is $40$ km/hr and Speed of the second train is $60$ km/hr
  2. Speed of the first train is $60$ km/hr and Speed of the second train is $80$ km/hr
  3. Speed of the first train is $100$ km/hr and Speed of the second train is $80$ km/hr
  4. Speed of the first train is $70$ km/hr and Speed of the second train is $90$ km/hr
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the speeds be v and v+20. In 2 hours, the trains cover a combined distance of 300 - 20 = 280 km. Thus, 2(v + v + 20) = 280, which simplifies to 2v + 20 = 140, so 2v = 120 and v = 60. The speeds are 60 km/hr and 80 km/hr.

AI explanation

Let the speed of the slower train be x, making the faster train's speed x plus 20. The total distance they cover together in two hours is 2x plus 2 multiplied by (x plus 20), which equals 4x plus 40. Since the initial distance is 300 km and 20 km is left after two hours, the total distance they covered is 280 km. Setting 4x plus 40 equal to 280 gives 4x equals 240, so x is 60 km/hr and the faster train is 80 km/hr.

Keep practicing — related questions