Here we know that the initial velocity of the car is given by:
And the final velocity of the car is given by:
It took 3 seconds to attain the final velocity, so we have
Therefore, the acceleration can be obtained by:
Plugging the values of the initial, final velocity and the time, we get:
So the acceleration of the car is given by:
Now we need to find the direction of the average acceleration of the car:
Here, x and y are the coefficients of the 'x' and 'y' components of the vector:
Therefore, the direction of the average acceleration of the car is .