Aptitude - Time and Distance - Discussion

Discussion Forum : Time and Distance - General Questions (Q.No. 2)
2.
An aeroplane covers a certain distance at a speed of 240 kmph in 5 hours. To cover the same distance in 1 hours, it must travel at a speed of:
300 kmph
360 kmph
600 kmph
720 kmph
Answer: Option
Explanation:

Distance = (240 x 5) = 1200 km.

Speed = Distance/Time

Speed = 1200/(5/3) km/hr.     [We can write 1 hours as 5/3 hours]

Required speed = 1200 x 3 km/hr = 720 km/hr.
5

Discussion:
162 comments Page 12 of 17.

Sai said:   1 decade ago
1200/5/3

= 1200*3/5 = 3600/5 = ?

Bhupesh shahare said:   1 decade ago
Still it confusing, how 5/3 comes?

Dhanshri said:   1 decade ago
s = d/t.

s1 = d1/t1.

s2 = d2/t2.

s1t1 = s2t2/distance is same.

t2 = s1t1/s2.

t2 = 240*5/(5/3).

t2 = 720.

Veerapandi E said:   1 decade ago
How come 5/3?

Divyan said:   1 decade ago
Why we are multiplying 240*5?

Because they 5hrs right. So it has to be 5*3600 right.

Manasa said:   1 decade ago
1 hr become 5/3hr as:

1 hr is 1/3 rd of part in 5hrs that means 1 = 3/3.
1 = (5-2)/3, 1 = (5/3)-(2/3), 1+(2/3) = 5/3,

Then 5/3 = 5/3.

Here it is proved 1hr is 1/3rd of part in 5hrs.

Jabi Mir said:   1 decade ago
Here, V1 = 240 km/h, T1 = 5 h, Also, V2= ?, T2 = 5/3.

We Know, V=S/T or S = VxT, But here distance is same,
Therefore, V1xT1=V2xT2, rearranging we get, V2 = V1xT1/T2.

Substituting values,
V2 = 240 x 5 / 5/3 or we can write it, V2 = 240 x 5 x 3/5.

On simplifying we get, V2=720 Km/h.
(1)

JEEVA said:   1 decade ago
240km--------5hr.
? --------5/3hr.

240*5/5/3 the 5/3 become 3/5 when it come up, the 5 can cut.
So finally we can 240*3 = 720kmph.

Udaya said:   1 decade ago
This can also be solved as:

Given d1 = d2.

=> s1*t1 = s2*t2.
240*5 = s2*5/3.

s2 = 240*5*3/5.
s2 = 720 kmph.

Vinayaga said:   1 decade ago
Why we use 1+2/3 ?


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