Answer:
Total number of cars in the parking lot are 80.
Explanation:
Let the number of cars = x and the number of trucks = y
Since, there are 1.5 times many cars than the truck, we get,
Number of cars = 1.5 time number of trucks
i.e.

Also, it is given that when 45 cars were added in the lot, 12 trucks left the parking lot.
So, we get,
Number of cars + 45 = Number of trucks - 12
i.e.

Finally, there are 17 cars more than the trucks.
We have the required equation,

i.e.

i.e.

i.e.

i.e. x= 80
Thus, the total number of cars in the parking lot are 80.