Answer:
1)
75 kmh⁻¹
2)
75 kmh⁻¹
Explanation:
1)
 = Speed of train from station A to station B = 80 kmh⁻¹
 = Speed of train from station A to station B = 80 kmh⁻¹
 = distance traveled from station A to station B
 = distance traveled from station A to station B 
 = time of travel between station A to station B
 = time of travel between station A to station B 
we know that 


 = distance traveled from station B to station C
 = distance traveled from station B to station C 
 = Speed of train from station B to station C = 60 kmh⁻¹
 = Speed of train from station B to station C = 60 kmh⁻¹

Total distance traveled is given as 

Total time of travel is given as 

Average speed is given as 

Given that :

So

2)
 = Speed of train from station A to station B = 80 kmh⁻¹
 = Speed of train from station A to station B = 80 kmh⁻¹
 = time of travel between station A to station B
 = time of travel between station A to station B 
 = distance traveled from station A to station B
 = distance traveled from station A to station B
we know that 


 = distance traveled from station B to station C
 = distance traveled from station B to station C 
 = Speed of train from station B to station C = 60 kmh⁻¹
 = Speed of train from station B to station C = 60 kmh⁻¹
 = time of travel for train from station B to station C
 = time of travel for train from station B to station C
we know that 


Total distance traveled is given as 

Total time of travel is given as 

Average speed is given as 

Given that :

So
