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:
209 comments Page 1 of 21.

Hello said:   3 weeks ago
@Mercy and @Raj.

18/5 is used when we convert metres per second to km per hour. And 5/18 is used when we convert km per hour to metres per second.

It is a shortcut. As we see 5km/hr to m/sec.
We usually do 5* (1000/60*60) =5* (1000/3600) =5* (10/36) =5* (5/18).
Thus, while converting from km/hr to m/s, using 5/18 is simple.
(3)

Soumya Ranjan said:   4 weeks ago
In 5min 600m,
In 1min, 600/5 = 120m,
In 1hr, 120 * 60 = 7200m,
1km = 1000m,
So, 7200m = 7.2km.
(26)

Majji deepika said:   1 month ago
Given data.

Distance(d) = 600m
Time(t) = 5m(converting into sec)
t = 5 * 60 = 300s.

Find : speed = ?(in km/hr)
Now apply the formulaic;
Speed =distance/time
Speed=600/300=2m/s
So, over answer is km/hr.

Now the formula is (a m/s=a*(18/5)km/hr)
Now apply
2m/s = 2 * (18/5)km/hr.
Speed = 7.2km/hr.
(6)

Dffse said:   1 month ago
Can anyone explain it clearly?
(4)

UMAKANT CHAUDHARY said:   2 months ago
Let's Convert distance metres to km;
600/1000 km = 0.6km.
Now, same as time, 5/60 = 1/12 hr.
Now speed = distance/time.
= 0.6/(1/12),
= 0.6 * 12,
= 7.2 km.
(30)

Suman said:   2 months ago
Thanks everyone, for giving a clear explanation.
(1)

Gajanan said:   2 months ago
Why it multiply with 18/5? Please explain.
(11)

Devendra rajput said:   2 months ago
Your Explanation is better than others. Thanks @Lavanya.
(4)

MERCY said:   3 months ago
How do we get 18/5? Please explain to me.
(18)

Raj said:   3 months ago
How 5/18 becomes 18/5? Anyone, please explain.
(15)


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