Aptitude - Problems on Trains - Discussion

One train will cover 20 km in one hour.

Now the distance remaining is 90 km.

So time take is equal to 90/20+25 = 2 hours means will meet 2 hours after 8 am i.e. 10 am.

@Chai.

Answer : 2.15 pm. Is this correct?

@Chai.

Sorry I will be confused. I got two answers by solving two different methods.

I got 2.15 pm and also I got 4.15 pm.

Let 't' b the time in hrs the two trains meet. Then distance traveled by 1st train is 20t and distance.

Traveled by 2nd train is 25 (t-1). Because 2nd train run after 1hr of 1st train.

Total distance = 110 km = 20t+25(t-1).

Solving we get t = 3hr. 7 a.m.+3hr = 10 a.m.

Simple solution no formula, no concepts just common sense.

Let us consider first train it's speed is 20 km/hr.

So it covers 20 kms in 1 hour.

Starting from 7 am 1st train second train from 8 am to 9 am.

At 8 am it covers 20 km at 9 am it covers 25 km. 9 am it covers 40 km 10 am it covers 50 km.

10 am === 60 km.

So at 10 am total distance covered by two trains is 60+50=110 km.

Which is the actual distance of separation between two train hence they meet each other so simple.

How we assume x=3 then how we get both meeting time at 10 please explain clearly to me.

@Chai.

Why do we have to take the distance 390 when we add this covered by A after x hours and this covered by B after x-1 hours then why we equal it to 390 km?

Here x=3 is answer how to convert into am/pm some other problem.

A train leaves P for Q; at the same time another train leaves Q for P. The trains meet after 6 hours, the train from P and Q having travelled 8 km per hour more than the other. If the distance from P and Q is 528 km, the speed of train from P and Q in km/hour is.

Please solve this?

The distance between two stations A and B is 110km.

1st Train starts at 7am at station A at a speed of 20kmph.
i.e. 1st train travels 20 kms in one hour.
Now The distance is 90kms.

2nd train stats at 8am at and travelling at a speed of 25kmph.
So, the Relative speed of two trains is 20 + 25 = 45kmph.
=> Time = Distance/Speed.
Time = 90/45 = 2hrs.
Requied answer is 8 A.M + 2hr =10 A.M.