A man travels 600km partly train and by car lf he covers 400km by train and rest by car it takes him 6hours 30min but if he travels 200km by a train and rest by car he takes half an hour longer find the speed of
train and that of car
Answers
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Answer:
➞ Speed of the train = 100 km/hr
➞ Speed of the car = 80 km/hr
Step-by-step explanation:
Given:
- Total distance travelled by the man = 600 km
- If the man travels 400 km by train and rest by car it takes him 6 hours and 30 minutes.
- If the man travels 200 km by train and the rest by car, he takes half an hour longer.
To Find:
- Speed of the train
- Speed of the car
Solution:
Let us assume the speed of the train as x km/hr.
Let the speed of the train be y km/hr.
By first case given,
Time taken to travel by train + Time taken to travel by car = 6 hours 30 minutes.
But we know that,
Time = Distance/Speed
Therefore,
Now by second case given,
Time taken to travel by train + Time taken to travel by car = 6.5 + 30 minutes.
Hence,
Now let 1/x = p and 1/y = q
Hence equation 1 and 2 changes to,
400p + 200q = 6.5-------(3)
200p + 400q = 7----------(4)
Multiply equation 3 by 2
800p + 400q = 13-------(5)
Solving equation 4 and 5 by elimination method,
-600p = -6
p = 1/100
Substitute the value of p in equation 4,
200 × 1/100 + 400q = 7
2 + 400q = 7
400q = 5
q = 5/400
q = 1/80
But we know that 1/x = p, x = 100 km/hr
Therefore the speed of the train is 100 km/hr.
Also, 1/y = q, y = 80 km/hr
Hence speed of the car is 80 km/hr.