Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 4)
4.
A train can travel 50% faster than a car. Both start from point A at the same time and reach point B 75 kms away from A at the same time. On the way, however, the train lost about 12.5 minutes while stopping at the stations. The speed of the car is:
Answer: Option
Explanation:
Let speed of the car be x kmph.
| Then, speed of the train = | 150 | x | = |  |
3 | x |  kmph. |
| 100 | 2 |
 |
75 | - | 75 | = | 125 |
| x | (3/2)x | 10 x 60 |
 |
75 | - | 50 | = | 5 |
| x | x | 24 |
| x = |
|
25 x24 | |
= 120 kmph. |
| 5 |
Discussion:
342 comments Page 31 of 35.
Srihari said:
1 decade ago
Tell me about 12.5/100*60 ?
Mysterious said:
1 decade ago
Friends......
let speed of car be x
thus, speed of train (150/100)x (stated that train is 50% faster than car)
now since the train lost 12.5 mins. i.e. the difference between time taken by car and time taken by train is 12.5 mins,
and since TIME=DISTANCE/SPEED
time taken by car= 75/x
time taken by train= 75/(150/100)x or 75/(3/2)x
and the difference between time taken by car and time taken by train is 75/x - 75/(3/2)x = 125/10*60.
x=120 kmph
let speed of car be x
thus, speed of train (150/100)x (stated that train is 50% faster than car)
now since the train lost 12.5 mins. i.e. the difference between time taken by car and time taken by train is 12.5 mins,
and since TIME=DISTANCE/SPEED
time taken by car= 75/x
time taken by train= 75/(150/100)x or 75/(3/2)x
and the difference between time taken by car and time taken by train is 75/x - 75/(3/2)x = 125/10*60.
x=120 kmph
Arun said:
1 decade ago
Rameez your explanation is great.
Sreekanth said:
1 decade ago
Think... Y 3/2x came with an example...
if u think car has x speed, then train ll have 2x.
then substitute x with simple value..
x:2x
if x=10 then
10:20
it mean train has double value of car speed.
but x:3/2x
then 10:15x
In which train has 50% faster than car.
50% of car is 5. so 10+5=15.
if u think car has x speed, then train ll have 2x.
then substitute x with simple value..
x:2x
if x=10 then
10:20
it mean train has double value of car speed.
but x:3/2x
then 10:15x
In which train has 50% faster than car.
50% of car is 5. so 10+5=15.
Kiru said:
1 decade ago
Thanks senhil I understand easily.
Prawinn said:
1 decade ago
Simple train and car reach the place in a same time if car takes 8 hours to reach the place train also take 8 hours that 8 hour be t+somewaste of time the diff b/w both train and car is 0.
So, t1-(t+x) = 0
=> t1-t = x .
So, t1-(t+x) = 0
=> t1-t = x .
Hemant Sharma said:
1 decade ago
Hi, its right, I'm little confuse that why calculate difference b/w both but car lost time 12.5.so the difference b/w boths time is equal to the lost time | i.e 12.5 is equal to the 125/10 and change into hrs so 125/(60*10) .
Rameez said:
1 decade ago
Let t' is the exact time of the train without stopping...
Let t is the exact time of the car
12.5 minutes is the wastage of time because of train stopping
Since in given problem it is said that both car & train arrives at same time....
Therefore t'+(125/600)=t
75/(3x/2)+125/600=75/x
75/x-75/(3x/2)=125/600
By solving it we get x=120Kmph
Let t is the exact time of the car
12.5 minutes is the wastage of time because of train stopping
Since in given problem it is said that both car & train arrives at same time....
Therefore t'+(125/600)=t
75/(3x/2)+125/600=75/x
75/x-75/(3x/2)=125/600
By solving it we get x=120Kmph
Atul said:
1 decade ago
(75/x)denotes time taken by car.
this means time taken by the car to cover the distance of 75 km with speed x.
(75/(3/2)x)denotes time taken by train to cover the 75 km distance with speed 3/2x.
in the problem it is said that train rest for 12.5 min at station
and both reach 75 km at same time.
There fore difference between the time is (75/x)-(75/(3/2)x)=12.5/60 in hrs.
this means time taken by the car to cover the distance of 75 km with speed x.
(75/(3/2)x)denotes time taken by train to cover the 75 km distance with speed 3/2x.
in the problem it is said that train rest for 12.5 min at station
and both reach 75 km at same time.
There fore difference between the time is (75/x)-(75/(3/2)x)=12.5/60 in hrs.
Hemant said:
1 decade ago
Explain the simple way, (75/x)-(75/(3/2)x)=12.5/60
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