# 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
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:
146 comments Page 1 of 15.

Hi, we know that speed=distance/time

Here distance is constant for different times
so speed o< 1/time
i.e
s1/s2=t2/t1

=> s2=s1*(t1/t2)

=> s2=240*[5/(5/3)]

=> s2=240*3

=> s2=720
here s2 is the speed when time is 5/3
remember when distance is constant speed o< 1/time
if speed constant time o< distance
if time is constant speed o< distance

Thanks.

Ramkumar,nothng hard in tat.first knw formula
distance=speed*time
speed=distance/time
time=speed/distance

now read the question.they given aeroplance covers distance of 240 km/hr in 5 hours so we need the total distance of 5 hours...
distance=speed*time
so distance=240*5=1200km
now we have to speed cover in 1+2/3 hours=5/3 hours
speed=distance/time
speed=(1200/5/3)kmph=(1200*3/5)kmph=720 kmph
(2)

Naren said:   9 years ago
Here they wrote fraction 5/3 as mixed numbers (1 2/3).

Let me explain how to write it.

Here, the whole number is 1.

The denominator is 3 and the numerator is 2.

I) 1st Multiply the whole number by the denominator. i.e. 3*1=3.

II) Add the result to the numerator: i.e 3+2=5.

III) Now The numerator is 5. The denominator remains 3. --> so 5/3.

We got the output.
(4)

Dayakar jitti said:   1 month ago
The given distance is =1200km.
speed =distance/time.

To cover the same is distance in 1^2/3 hours
which means we can write 1 power 2/3 as 1+2/3 therefore convert into fractions as,
1^2/3 = 1 + 2/3 = 3 * 1 + 2/3 which is 5/3 right so
according to the given problem we have to calculate the required speed.
Then speed =(1200 x 3/5)km/hr = 720 km/hr.
(3)

Sheela m b said:   1 decade ago
observe the formula carefully.
Distance = (240 x 5) = 1200 km.

Speed = Distance/Time
it says speed equals distance travelled by time taken and hence,
Speed = 1200/(5/3) km/hr.
since time is 5/3, the denominator(here it is 3) of denominator(the whole 5/3)becomes numerator. Therefore the following.
Required speed = 1200 x 3 km/hr = 720 km/hr.

RAPTOR said:   9 years ago
In the question I read it as to find the speed to cover the same distance in 1 hour (not as 1 2/3).

My logic is, since the total distance calculated is 1200 km, and in one hour it should cover the same distance, my answer is right.

Vaidik said:   3 years ago
According to the tri-rashi method.

5hours ----------->240km/h.
5/3hours ---------> (?).

5 x 240/5 x3 =80kmph.

I know this is wrong but speed should increase here because time is decreasing but I want to know why this method is not applicable here. Please can anyone help me to solve this?
(2)

Jabi Mir said:   10 years 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)

Prabakaran said:   6 years ago
On the first, the trail the aeroplane cross the distance in 5 hours at the speed of 240 km/hr.

For the same distance in 1(2/3) hours to resolve this cross multiplication (3*1*2-3= 3 hr).
So we have to multiply 240*3 to get the value of second trail speed is 720 km/hr.

Deepak said:   8 years ago
Distance = 240, 5 hour.

To cover same distance = x, 5/3 hour.

1 hour = 60 minutes, 5 hour = 300 minutes, 5/3 hour = 100 minutes.

= (5/3*60 minutes = 100 minutes).

= 240*300 = x*100.

72000 = x*100.

x = 72000/100.

x = 720.

So speed is 720 kmph.