Two trains are coming from opposite directions with speeds of 75 km/hr and 100 km/hr on two parallel tracks. At some moment the distance between them is 100km. After T hours, distance between them is again 100km. T is equal to:

1. 1.5 hrs
2. $$1\frac{1}{7}$$ hrs
3. 1 hr
4. 2 hrs

A

1

B

2

C

3

D

4