Question

Two stations P and Q are 140 km apart from each other. One of the two trains, having different speeds, starts from P and the other starts from Q at the same time. If they travel towards each other, they meet after 1 hour. If they travel in the same direction, they meet in 7 hours. Find their speeds.

80 km/h, 60 km/h
40 km/h, 60 km/h
60 km/h, 70 km/h
90 km/h, 70 km/h

Answer 1

Hello !
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Distance travel by train P in 7 hours = 140 km + distance covered by Train Q in  hours 


x km /hr X 7 hour = 140 km + y km/hr X 7 hour 

7x = 140 + 7y 

x   = 20 + y 

x - y = 20 _______________(1) 
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Distance travelled by Train P in  1 hour  + distance travelled by Train Q in 1 hour  = 140 km

x km/hr x 1 hour  + y km/hr x 1 hour  = 140 km 

x + y  = 140 _________(2) 

By  adding 1 and 2 we get 
2x = 160 
x = 80 
y = 140 - 80 = 60 
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So option a is correct 

Answer 2

Here is the answer for question in an attachment .Please have a look at it.

There is a complete answer written .

Please find the other image in attachment.

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Hope​ my answer helped !

Thanks !