ANSWER
72km/h
EXPLANATION
The average speed of the car can be calculated using the formula:
Average Speed=total distance/ total time taken.
The car covers a distance of 108km in 1½ hours.
We substitute the values into the formula to obtain,
[tex]Average \: \: Speed= \frac{108}{1.5} [/tex]
[tex]Average \: \: Speed=72 {kmh}^{ - 1} [/tex]
Therefore the average speed of the journey is 72km/h
