Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 8)
8.
The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 km in 4 hours, then the speed of the first train is:
Answer: Option
Explanation:
Let the speed of two trains be 7x and 8x km/hr.
| Then, 8x = |  |
400 |  |
= 100 |
| 4 |
 x = |
|
100 | |
= 12.5 |
| 8 |
Speed of first train = (7 x 12.5) km/hr = 87.5 km/hr.
Discussion:
51 comments Page 4 of 6.
Vellamuthu said:
1 decade ago
Ratio 7:8
Speed =400/4 km/hr
speed =x
x=400/4 km/hr
4x=400 km
Second train Ratio 8*50=400=4x
Ratio 7*50=4x
350=4x
x=350/4
x=350/4
x=87.5 km/hr
Speed =400/4 km/hr
speed =x
x=400/4 km/hr
4x=400 km
Second train Ratio 8*50=400=4x
Ratio 7*50=4x
350=4x
x=350/4
x=350/4
x=87.5 km/hr
Mihir jack said:
1 decade ago
Let this try :
Assume 7:8 = 7/8 = 0.875
Now 0.875 % less speed than 2nd train ,
Now simple 0.875 *100 = 87.5 answer
Assume 7:8 = 7/8 = 0.875
Now 0.875 % less speed than 2nd train ,
Now simple 0.875 *100 = 87.5 answer
Amala said:
1 decade ago
7:8
100kmph - 8
? - 7 ( so cross multiplication)
(7*100)/8=87.5
100kmph - 8
? - 7 ( so cross multiplication)
(7*100)/8=87.5
Rahul said:
1 decade ago
Train 2 speed is 100km/hr
100/8=12.5
12.5*7=87.5 train 1 speed =answer
100/8=12.5
12.5*7=87.5 train 1 speed =answer
Avnish poddar said:
1 decade ago
Let speed of first train is "x"
And speed of second train is ""y"
Therefore given ratio are (x/y) = (7/8).
x = (7/8)*y = 87.5 kmph : Answer.
Where y =(400/4) = 100.
And speed of second train is ""y"
Therefore given ratio are (x/y) = (7/8).
x = (7/8)*y = 87.5 kmph : Answer.
Where y =(400/4) = 100.
Manish Singh said:
1 decade ago
7/8 = X/(400/4).
Now find the X,
It will come 87.5 KM/hr.
Here X is the speed of first train.
Now find the X,
It will come 87.5 KM/hr.
Here X is the speed of first train.
Naga said:
1 decade ago
How to solve the problems in less time please explain simple techniques or any tricks?
Ophi said:
1 decade ago
Step 1 :
Find the speed of the Second train.
Runs at 400kms in 4 hours, S=D/T.
400/4 = 100kms/hr.
Step 2 :
Find the speed of first train.
Let speed of first train be "x".
By comparing the Ratio.
7:8 = x:100.
Then 8x = 7*100.
x = 700/8.
= 87.5km/hr.
Find the speed of the Second train.
Runs at 400kms in 4 hours, S=D/T.
400/4 = 100kms/hr.
Step 2 :
Find the speed of first train.
Let speed of first train be "x".
By comparing the Ratio.
7:8 = x:100.
Then 8x = 7*100.
x = 700/8.
= 87.5km/hr.
Awesomeness said:
1 decade ago
This problem was really easy!:).
Suhail ahmed g said:
8 years ago
We can do it directly,
400/4=100,
(7/8)*100=87.5.
400/4=100,
(7/8)*100=87.5.
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