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:
345 comments Page 28 of 35.
Trishita said:
7 years ago
Dist=speed*time.
Let, speed of car=100x.
Speed of train=150x (as 50% faster).
So..Time taken by car= dist/speed=75/100x.
And by train=75/150x.
And train lost 12.5 min=12.5/60 hr =125/600 hr.
This time is equal to the time taken b/w car and train i.e;
75/100x - 75/150x =125/600.
Solving this eq we get x=6/5.
So, the speed of car is=100*(6/5)= 120km/hr.
Let, speed of car=100x.
Speed of train=150x (as 50% faster).
So..Time taken by car= dist/speed=75/100x.
And by train=75/150x.
And train lost 12.5 min=12.5/60 hr =125/600 hr.
This time is equal to the time taken b/w car and train i.e;
75/100x - 75/150x =125/600.
Solving this eq we get x=6/5.
So, the speed of car is=100*(6/5)= 120km/hr.
Ershaad shah said:
7 years ago
@Trishita.
Can you please explain, how do you put 75/100x-75/150x = 125/600?
Can you please explain, how do you put 75/100x-75/150x = 125/600?
Ratul said:
7 years ago
Actually, it is time of car to cover the required distance and train take same time but including 12.5 minutes.
So both take same time you can rearrange the formula to understand easily.
(75/x) = (12.5/60)+-(75/(3/2)x).
So both take same time you can rearrange the formula to understand easily.
(75/x) = (12.5/60)+-(75/(3/2)x).
Ashish patil said:
7 years ago
Dist = speed * time.
Let, the speed of car=100x.
Speed of train=150x (as 50% faster).
So, Time taken by car= dist/speed=75/100x.
And by train=75/150x.
And train lost 12.5 min=12.5/60 hr =125/600 hr.
This time is equal to the time taken b/w car and train i.e;
75/100x - 75/150x =125/600.
Solving this eq we get x=6/5.
So, the speed of car is=100*(6/5)= 120km/hr.
Let, the speed of car=100x.
Speed of train=150x (as 50% faster).
So, Time taken by car= dist/speed=75/100x.
And by train=75/150x.
And train lost 12.5 min=12.5/60 hr =125/600 hr.
This time is equal to the time taken b/w car and train i.e;
75/100x - 75/150x =125/600.
Solving this eq we get x=6/5.
So, the speed of car is=100*(6/5)= 120km/hr.
Bhavi said:
7 years ago
Speed of train =( 1 + 50% )of speed of car.
75/t-12.5 = (1+1/2)75/t,
t=37.5 minutes,
Car speed = (2/3) * train speed,
Car speed = (2/3)*75/(37.5-12.5),
Car speed = 2 kmpm,
2 * 60 = 120 kmph.
75/t-12.5 = (1+1/2)75/t,
t=37.5 minutes,
Car speed = (2/3) * train speed,
Car speed = (2/3)*75/(37.5-12.5),
Car speed = 2 kmpm,
2 * 60 = 120 kmph.
Sameer azmi said:
7 years ago
The train speed of the train is 50% more the speed of the car = x + 50%x/100.
Then, (100x+50x) /100.
Then, (100x+50x) /100.
Gete Basu Chakma said:
7 years ago
The speed of car = x.
speed of train = 1.5x.
The lost time=12.5/60 = 5/24 hr.
The time taken by car = lost time +running time of train.
75/x = (5/24) +75/1.5x.
Then, x =120km/hr.
speed of train = 1.5x.
The lost time=12.5/60 = 5/24 hr.
The time taken by car = lost time +running time of train.
75/x = (5/24) +75/1.5x.
Then, x =120km/hr.
Zama said:
7 years ago
@All.
Explanation of this part, 12.5/10 * 60.
12.5 is 125/10.
=> 125/10*60,
=> 5*25/10*60, #since 125 can be written as 5*25.
=> 25/10*12, #after cancelling denominator 60 by numerator 5 as 5*12=60.
=>25/120, #here cancellation goes as 5*5=25 & 5*24=120.
=>5/24.
Hence, we got 5/24.
Explanation of this part, 12.5/10 * 60.
12.5 is 125/10.
=> 125/10*60,
=> 5*25/10*60, #since 125 can be written as 5*25.
=> 25/10*12, #after cancelling denominator 60 by numerator 5 as 5*12=60.
=>25/120, #here cancellation goes as 5*5=25 & 5*24=120.
=>5/24.
Hence, we got 5/24.
RAMJAN RAEEN said:
7 years ago
Can anyone explain to me how 75/X - 75/ (3x/2) = 12.5?
How the time is the same in both case car and train if a halt is not considering?
How the time is the same in both case car and train if a halt is not considering?
Ansh gupta said:
7 years ago
Can you explain how 150/100x came?
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