Aptitude - Problems on Trains - Discussion

Hi, @Chai.

I got 1:25 PM. Is this correct?

Easy way:

d = 110 km
train A = starts @ 7.00 with speed = 20 km
train B = starts @ 8.00 with speed = 25 km *(5kms difference A & B)

So, A+B=45 kms && d = 110
---> Time = d/s = 110/45 (after cancellation = 22/9)
---> Now add 5 (difference kms between 2 trains speed) to 22 = 27.
---> Now divide 27/9 = 3
---> Add 3 am to 7 am = 10 am.

**Here the difference in time is only 1 hr so added only 5 km's extra.

If the time difference was 2 hrs then we 10 and so on. If the answer you get doesn't match with the options then choose the closest options. The simple reason is time has 60 min where as when you are actually calculating it is of 100. Hope you'll are understanding.

HOPE THIS WORKS I WAS ACTUALLY TRYING TO MAKE SOME EASY SHIT SO THAT THIS TYPE OF SUMS BECOMES EASY FOR THE US :-)

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.

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?

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

@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?

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

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.

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.

@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.