Explanation

Time = Distance / Speed

Original time = 240 / v

New time = 240 / (v + 20)

Difference is 1 hour

So

240/v - 240/(v+20) = 1

Multiply both sides

240(v+20) - 240v = v(v+20)

4800 = v2 + 20v

v2 + 20v - 4800 = 0

v2 + 80v - 60v - 4800 = 0

v(v+80) - 60(v+80) = 0

(v+80)(v-60) = 0

v = 60

Last verified on 17-10-2026

Explanation

Convert the speeds of the trains from km/h to m/s

1 km/h = 1000 m/3600 s

Speed of the first train = 60 km/h = (60,000 m/3600 s) m/s = 16.67 m/s.

Speed of the second train = 45 km/h = (45,000 m/3600 s) m/s = 12.50 m/s.

Relative speed = Speed of the first train - Speed of the second train = 16.67 m/s - 12.50 m/s = 4.17 m/s.

Distance = Length of the second train = 500 meters.

Using the formula:

Distance = Speed × Time

Time = Distance / Relative speed = 500 meters / 4.17 m/s = 120.05 seconds.

To convert the time from seconds to minutes, we divide by 60:

Time in minutes = 120.05 seconds / 60 = 2 minutes (approximately).

Therefore, the first train will cross the second train after approximately 2 minutes.

Last verified on 13-10-2026

Explanation

Explanation

Total Distance = 300 + 300 = 600 km

Total Time = 4 + 6 = 10 hours

Average Speed = Total Distance / Total Time

= 600 / 10 = 60 km/h

Last verified on 12-10-2026

Explanation

Total distance to cover = Train length + Platform length

= 150 + 250 = 400 m

Speed = 60 km/hr = 60 × 5/18 = 50/3 m/sec

Time = Distance / Speed

= 400 / (50/3)

= 400 × 3 / 50

= 24 seconds

Last verified on 12-10-2026