Answer:
The speed and time are directly proportional in that the higher the speed the lesser the time and vice versa.
The constant is the total distance which is 180 km
Step-by-step explanation:
Step one:
given data
The distance between the  two cities is 180km
1.The distance was covered by a car at the rate of 50km/h
The time taken will be 
velocity= distance/time
time= distance/velocity
time= 180/50
time= 3.6 hours
2.The distance was covered by a bus 45km/h
The time taken will be 
velocity= distance/time
time= distance/velocity
time= 180/45
time= 4 hours
3.The distance was covered by a bicycle at 25km/h
The time taken will be 
velocity= distance/time
time= distance/velocity
time= 180/25
time= 7.2 hours
 
        
             
        
        
        
Answer:
w+14, 
Step-by-step explanation:
 
        
             
        
        
        
Answer:
6.813·10^7
Step-by-step explanation:
Multiplying 0.0000006813 by 10^7 will move the decimal point 7 places to the right, resulting in 6.813.
Conversely, multiplying 6.813 will move the decimal point 7 places to the left, producing the original decimal fraction.
Therefore, 
0.0000006813 = 6.813·10^7