Answer:
They collide after

Step-by-step explanation:
The time in which the two cars collide will be equal to the time in which they two cover the distance 'D'.
Let the cars meet after 't' time
Distance covered by toy car travelling at a constant velocity equals

Distance that the accelerating car travles in the same time 't' can be obtained from second equation of kinematics as

Now the condition dictates that

Solving the quadratic equation for 't' we get

We neglect negative value since time cannot be negative.