Aptitude - Time and Distance - Discussion

Hi guys. I'm still confused. How did you compute 60x5/18 manually? How did you get the answer 50/8? Explain in detail.

How it is coming 18÷5? Please explain it.

Hey, guys, The sum is relatively easy if you know how and while there are some good examples above, it can be broken down even further in the order you can understand it better, especially when it comes to 18/5 part of the formula. So let's break it down (sorry for the long explanation and simple steps).

PART 1

1. Divide the Distance by the time: 600m / 5min = 120m/min.
2. Divide the new Distance (120m/min) by 60 (the number of seconds in a minute) to give you the distance travelled per second: 120m/min / 60 = 2m/sec.

PART 2

We have established that we are travelling at 2m/sec (write that down and leave it for now, we will come back to this later). Now we need to breakdown 1Km into meters (1000m) and 1hour into seconds in order to change from meters per second to Kilometres per hour.

1. 1 Kilometre in length is 1000m (simple)
2. Next work out how many seconds are in 1 hour of time. There are 60min in an hour and 60 seconds in each minute, therefore to get the total seconds we must Multiply 60min with 60 Seconds: 60min x 60Sec = 3600Sec in 1hr of time.
3. This now leaves us with 3600/1000. At this point we can complete the question and there is no real need to break it down further, please follow the example: 2m/sec x 3600sec / 1000m = 7.2Kph

4, However, for those of you still wondering where they got 18/5 from, the above numbers can be broken down further to make it easier to work with if you are not using with a calculator etc. if you were to remove the zeros from 3600/1000 you are left with 36/10 and if you were to half these numbers again you will come to 18/5 (and so on). You can apply both these number to the same sum and the results will be the same, you have just made it easier to calculate:

Answer 1:
600 / 5 = 120 / 60 = 2m/sec
1km = 1000m
1hr: 60 x 60 = 3600sec
2 x 3600 / 1000 =7.2

Answer 2:
600 / 5 = 120 / 60 = 2m/sec
1km = 1000m
1hr: 60 x 60 = 3600sec
36/10
2 x 36/10 = 7.2

Answer 3:
600 / 5 = 120 / 60 = 2m/sec
1km = 1000m
1hr: 60 x 60 = 3600sec
36/10
18/5
2 x 18/5 =7.2

I hope this helped?

Very nice solution. Thanks.

Thank you guys for the explanation.

We know that s=d/t,
d=600m and t=5m,
we know that,
1min.=60sec,
therefore, 5min=5*60=300sec,
600/300,
= 2.

2 * 18/5 = 7.2m/m.

Thanks for the explanation friends.

We know that speed=(distance / time).
so speed=(600/300)=2m/s.
2m/s= 2(18/5)=7.2km/hr.

Hi everyone,

Speed = Distance/Speed
Time= Distance/Speed
Distance=Speed x Time

1km=1000m,and 1hr=3600seconds
Therefore, 1km/hr=1000m/3600sec =5m/18sec=5/18m/s.

Therefore,
to change a speed in km/hr to a speed in m/sec, multiply by5/18.
Conversely, to change a speed in m/sec to a speed in km/hr, multiply by 18/5.

Distance= 600 metres.
Time= 5min
Speed =?
Speed = distance/time.
Speed = 600/5=120 m/sec.
Because,
1min=60min
120 min= 120*60 min= 7200 min.
Because,
1 km = 1000 metre.
7200 metre / 1000 metre =7.2 km/hr prove that.