Aptitude - Time and Distance - Discussion

Discussion Forum : Time and Distance - General Questions (Q.No. 1)
1.
A person crosses a 600 m long street in 5 minutes. What is his speed in km per hour?
3.6
7.2
8.4
10
Answer: Option
Explanation:

Speed = 600 m/sec.
5 x 60

   = 2 m/sec.

Converting m/sec to km/hr (see important formulas section)

   = 2 x 18 km/hr
5

   = 7.2 km/hr.

Discussion:
220 comments Page 19 of 22.

Sandip said:   1 decade ago
Simply,

One man cover 600 m in 5 minute
first calculation wht is dist cover for 1 minute
600mtr/5min = 120meter is cover per(1) minute
qus is find the km/perhour
1hour=60minute
120mtr*60minute = 7200meter is cover in 1hour(60minute)
find km
1000meter=1km
=7200/1000=7.2 km/perhour

Swayam said:   1 decade ago
@Priya.

Our question is why we convert 5 min into seconds. Its because of the formula i.e. if speed of the body is 'a'm/sec then when we convert it into km/sec, it becomes (a*18/5) km/sec. In both cases time is required in sec. So it is necessary to convert 5 min into sec. Ok ?

Priya said:   1 decade ago
Why we convert 5 min into seconds?

Ravichandran said:   1 decade ago
600=5minutes therefore

120= 1 minute

60*120=7200 meters

Kilometer per hour = 7.2
Thats all

Riyazahmad said:   1 decade ago
Its simple, no need to go through 18/5. do one thing,

1st convert m/s into km/hr i.e. (2m/s=2*3600/(1000)) after doing this calculation you will get {7.2 km/hr}

Ganesh said:   1 decade ago
To convert km/hr to m/sec, we hav to do in dis way.....
1km=1000m
1hr=3600sec
1km/hr=1000/3600 m/sec
therefore 1km/hr=5/18 m/sec


Similarly to convert m/sec, we hav to in reverse way.....
1000m=1km ---> m=1/1000km
3600sec=1hr ---> sec=1/3600hr
its just a normal cross multiplication
m/sec=3600/1000 km/hr
therefore m/sec=18/5 km/hr

Vijay said:   1 decade ago
Please, dear. Not understand the conversion of the m/sec to km/sec. Please tell me brifely.

Seshu said:   1 decade ago
In above problem clearly given that for 5 minutes travelled distance is 600 mtrs.multiplied with 12 on both sides then we get one hour travelled distance i.e. 12*5mnts is 12*600mts = 7.2 km.

Vinoth said:   1 decade ago
A person is running at a speed of 18km/hr After one min a bomb blasts . Sound travels at 330m/s. How long does the man run before he cud he hear the sound??

How to solve this question?

Vino said:   1 decade ago
And onething before attempting the answers. We should study the formulas. Hence it is given in Important formulas. We must calculate using by mentioned formulas.


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