Explanation:
First, we need to determine the distance traveled by the car in the first 30 minutes,  .
.
Notice that the unit measurement for speed, in this case, is km/hr. Thus, a unit conversion of from minutes into hours is required before proceeding with the calculation, as shown below
                                           
Now, it is known that the car traveled 40 km for the first 30 minutes. Hence, the remaining distance,  , in which the driver reduces the speed to 40km/hr is
 , in which the driver reduces the speed to 40km/hr is
                                               .
.
Subsequently, we would also like to know the time taken for the car to reach its destination, denoted by   .
.
                                                .
.
Finally, with all the required values at hand, the average speed of the car for the entire trip is calculated as the ratio of the change in distance over the change in time.
                                                      
Therefore, the average speed of the car is 50 km/hr.
 
        
             
        
        
        
True . this is called a complex substance
        
                    
             
        
        
        
The people of Florida are closest to the equator and also near 2 different bodies of water and have rivers running thru them as well salt water and fresh water. they need alot of freshwater due to monsoon seasons, hurricanes etc, its humid and hot there so naturally you need to water more often and frequently.
        
                    
             
        
        
        
The combustion of fossil fuels is releasing more co2 into the atmosphere then what would occur naturally