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:
343 comments Page 17 of 35.
Madhu said:
8 years ago
@Bdboy Hasan.
How do you say car's speed is 3x?
How do you say car's speed is 3x?
Raihan Bangladesh said:
8 years ago
Let, car speed = X km/min.
Train speed = X + x* (50/100) Km/min.
=X+X/2 km/min.
=3X/2 km/min.
Time of car t =75/X.
Time of Train t =75/ (3X/2).
According to the question.
75/X=75/ (3X/2) +12. 5.
>> 75/X-150/3X=12. 5.
>> (225-150) /3X=12. 5.
>> 75 = 37. 5X.
>> X = 2 Km/min.
So car speed 1 minute to 2 km.
Car Speed 60 minutes to (60*2) = 120 km/h.
Train speed = X + x* (50/100) Km/min.
=X+X/2 km/min.
=3X/2 km/min.
Time of car t =75/X.
Time of Train t =75/ (3X/2).
According to the question.
75/X=75/ (3X/2) +12. 5.
>> 75/X-150/3X=12. 5.
>> (225-150) /3X=12. 5.
>> 75 = 37. 5X.
>> X = 2 Km/min.
So car speed 1 minute to 2 km.
Car Speed 60 minutes to (60*2) = 120 km/h.
(1)
Rahul said:
8 years ago
@Jignesh.
Time is given in minutes. So to change it in hours, it is divided by 60.
And 10 has been placed for the decimal point.
Time is given in minutes. So to change it in hours, it is divided by 60.
And 10 has been placed for the decimal point.
Rahul said:
8 years ago
Let Car speed = x kmph.
Train's speed is 50% more than car.
So, train's speed = x + 50x/100.
= 150x / 100.
= 3x/2.
Train's speed is 50% more than car.
So, train's speed = x + 50x/100.
= 150x / 100.
= 3x/2.
JIGNESH said:
8 years ago
How can 125/ (10 x 60) came? Please Explain me.
Harika said:
8 years ago
I understood. Good explanation @Dhinesh.
Rias said:
8 years ago
75km/s * 60 second = 4500sec,
50%-12.5 the train lost =37.5,
Speed = Distance/time.
then 4500sec/37.5 = 120km.
50%-12.5 the train lost =37.5,
Speed = Distance/time.
then 4500sec/37.5 = 120km.
(1)
Mithlesh said:
8 years ago
Nice explanation @Sushil.
Nayem said:
8 years ago
Let speed of car = x (km/h).
So, speed of train = x + 50% of x = x + x/2 = 3x/2 (km/h),
To travel 75 km, car needs time of 75/x hours,
To travel 75 km, train needs time of 75/(3x/2) hours + 12.5/60 hours,
As the two reach destination on same time on the clock, so these times should be equal. That is:
75/x = 75/(3x/2) + 12.5/60,
=> 75/x = (75*2)/3x + 12.5/60,
=> 75/x = 50/x + 12.5/60,
=> 75/x - 50/x = 12.5/60,
=> 25/x = 12.5/60,
=> 12.5x = 25 * 60,
=> x = 1500/12.5.
So, x = 120 (km/h).
So, speed of train = x + 50% of x = x + x/2 = 3x/2 (km/h),
To travel 75 km, car needs time of 75/x hours,
To travel 75 km, train needs time of 75/(3x/2) hours + 12.5/60 hours,
As the two reach destination on same time on the clock, so these times should be equal. That is:
75/x = 75/(3x/2) + 12.5/60,
=> 75/x = (75*2)/3x + 12.5/60,
=> 75/x = 50/x + 12.5/60,
=> 75/x - 50/x = 12.5/60,
=> 25/x = 12.5/60,
=> 12.5x = 25 * 60,
=> x = 1500/12.5.
So, x = 120 (km/h).
Ravi kataria said:
8 years ago
As a train is much faster, then time difference must be [distance /train speed - distance /car speed =12.5min].
Then, how it does inversely?
Then, how it does inversely?
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