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 | ![]() |
100 | 2 |
![]() |
75 | - | 75 | = | 125 |
x | (3/2)x | 10 x 60 |
![]() |
75 | - | 50 | = | 5 |
x | x | 24 |
![]() |
![]() |
25 x24 | ![]() |
= 120 kmph. |
5 |
Discussion:
342 comments Page 25 of 35.
Ankur Bravo said:
8 years ago
Let me clear this.
We can assume the speed of car as X
Now the speed of train (as per question) = X+X/2 = 3X/2
Distance (as per question) = 75 km
So time = distance/speed
For car its= 75/x
For train = 75/3x/2 now multiply 2 to 75 = 150/3x = 50/x
Now we have to add waist time to the train speed = 50/x+ 12.5/60
12.5/60 because time is given in minutes and we need it in hour so multiply 12.5 with 1/60 So it's = 12.5/60 or we can write it like 125/600= 5/24
Now the new speed of the train is 50/x+ 5/24.
put car speed = trains speed
75/x = 50/x+5/24.
or
75/x -50/x =5/24.
or
75 - 50
--------- = 5/24.
x
or
25/x = 5/24.
cross multiply.
24*25 = 5x.
600 = 5x.
x= 120 kmph.
We can assume the speed of car as X
Now the speed of train (as per question) = X+X/2 = 3X/2
Distance (as per question) = 75 km
So time = distance/speed
For car its= 75/x
For train = 75/3x/2 now multiply 2 to 75 = 150/3x = 50/x
Now we have to add waist time to the train speed = 50/x+ 12.5/60
12.5/60 because time is given in minutes and we need it in hour so multiply 12.5 with 1/60 So it's = 12.5/60 or we can write it like 125/600= 5/24
Now the new speed of the train is 50/x+ 5/24.
put car speed = trains speed
75/x = 50/x+5/24.
or
75/x -50/x =5/24.
or
75 - 50
--------- = 5/24.
x
or
25/x = 5/24.
cross multiply.
24*25 = 5x.
600 = 5x.
x= 120 kmph.
SSS said:
8 years ago
Just read the question carefully.
Both car and train starting and finishing at a same time that means they are taking the same time to reach A to B.
now we know that,
time=distance/speed
distance= 75
speed of car = x
speed of train = speed of car + 50% of speed of car = x+[50/100]x or 3x/2
now
travelling time of car = time taken in travelling +no waiting
75/x + no waiting
time of train = time taken in the travelling + waiting
= 75/[3x/2] + 12.5/60 hr
and both times are equal as in question it is given they are starting and reaching at the same time let we compare them.
75/x =75/[3x/2] + 12.5/60
which will give x= 50.
Both car and train starting and finishing at a same time that means they are taking the same time to reach A to B.
now we know that,
time=distance/speed
distance= 75
speed of car = x
speed of train = speed of car + 50% of speed of car = x+[50/100]x or 3x/2
now
travelling time of car = time taken in travelling +no waiting
75/x + no waiting
time of train = time taken in the travelling + waiting
= 75/[3x/2] + 12.5/60 hr
and both times are equal as in question it is given they are starting and reaching at the same time let we compare them.
75/x =75/[3x/2] + 12.5/60
which will give x= 50.
Vickivignesh said:
8 years ago
speed : car=x;train =y;
x=100% of speed;y=150% of speed; from this wkt, train covers a 150 km per hour but as we know from the detail.
It loses the 12.5 min due to stoppages.so it covers the 150km in 47.5min.
Speed=distance/time.(150*60/47.5)=180kmph.so train speed is 180kmph.
Hence car speed is 120kmph.
x=100% of speed;y=150% of speed; from this wkt, train covers a 150 km per hour but as we know from the detail.
It loses the 12.5 min due to stoppages.so it covers the 150km in 47.5min.
Speed=distance/time.(150*60/47.5)=180kmph.so train speed is 180kmph.
Hence car speed is 120kmph.
Shivani said:
8 years ago
Could we take 75/ (3/2) x before 75/x ?
Nilakshi said:
8 years ago
Time taken by train minus time taken by the car is how come that?
Noshiya said:
8 years ago
Can you please explain 150/100x=3/2x?
MOHAMMAD MOHSIN said:
8 years ago
Hi, now see a simple and driveway.
Train speed is 50% more than car speed it"s given
Now,
Lets the speed of car be x and 50% of x be x*50/100=x/2.
The speed of the train is x+50% more than car (x/2) =3x/2
Now,
At the same time, both cover same distance ie. 75km so,
75/x=75/3x/2 .
But it is also given that train stop at any station nd waste time 12.5 minutes (and we have to change it in km/hr so it becomes 125/10 same as 12.5 divides it by 60 to make it in hour=125/10*60).
From question, we understand speed of the train is more than car so it reaches first but both reach at same time due to train stop at any station so,
To calculate speed of car,
75/x- (75/3x/2+125/10*60) =0 (according to question (75/3x/2+125/10*60) is the time taken by train to calculate same distance) now,
75/x-75/3x/2=125/600.
75/x-50/x=25/120.
25/x=25/120.
1/x=1/120.
X=120km/h is the speed of car now,
I think everyone understands and get the answer. thank you.
Train speed is 50% more than car speed it"s given
Now,
Lets the speed of car be x and 50% of x be x*50/100=x/2.
The speed of the train is x+50% more than car (x/2) =3x/2
Now,
At the same time, both cover same distance ie. 75km so,
75/x=75/3x/2 .
But it is also given that train stop at any station nd waste time 12.5 minutes (and we have to change it in km/hr so it becomes 125/10 same as 12.5 divides it by 60 to make it in hour=125/10*60).
From question, we understand speed of the train is more than car so it reaches first but both reach at same time due to train stop at any station so,
To calculate speed of car,
75/x- (75/3x/2+125/10*60) =0 (according to question (75/3x/2+125/10*60) is the time taken by train to calculate same distance) now,
75/x-75/3x/2=125/600.
75/x-50/x=25/120.
25/x=25/120.
1/x=1/120.
X=120km/h is the speed of car now,
I think everyone understands and get the answer. thank you.
Frustrated engineer said:
8 years ago
A train can travel 50% faster than a car.
That means IF CAR SPEED IS X, THEN TRAIN SPEED SHOULD BE 2X. Double speed of car. So how can you guys say 50% more speed?
How this 150x/100 comes?
That means IF CAR SPEED IS X, THEN TRAIN SPEED SHOULD BE 2X. Double speed of car. So how can you guys say 50% more speed?
How this 150x/100 comes?
MikesMatE said:
8 years ago
@ALL.
150x/100 is to say that if the car travelled at x speed which is 100%x=x, then the train was 50% faster than that, 2x is an addition of 100% to x not 50%.
Therefore to add 50% to x would be to add 1/2x which makes it 3/2x.
150x/100 is to say that if the car travelled at x speed which is 100%x=x, then the train was 50% faster than that, 2x is an addition of 100% to x not 50%.
Therefore to add 50% to x would be to add 1/2x which makes it 3/2x.
Loganayaki said:
8 years ago
Car speed is X , and train speed is 50percent faster. Therefore train speed is,
=>car's speed + 50percent of car's speed.
=> x + (50*x)/100,
=>(100x+50x)/100,
=> 150x/100,
=>3x/2 is the speed of train.
=>car's speed + 50percent of car's speed.
=> x + (50*x)/100,
=>(100x+50x)/100,
=> 150x/100,
=>3x/2 is the speed of train.
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