question_answer

The distance between two cities A and B is 330 km. A train starts from A at 8 am and travels to words B at 60 km/h. Another train starts from B at 9 am and travels towards A at 75km/h. At what time do they meet?

A)  10 am             

B)  10 : 30 am

C)  11 am 

D)  11: 30 am

Correct Answer: C

Solution :

Distance travelled by first train in one hour \[=60\times 1=60\,km\] Therefore, distance between two train at 9 am             \[=330-60=270\,\text{km}\] Now, Relative speed of two trains             \[=60+75=135\,\text{km/h}\] \[\therefore \] Time of meet of two trains             \[=\frac{270}{135}=\] After 2 h