Answer: The required probability is 0.10.
Step-by-step explanation: Given that Marla is looking for a new car. She has test-driven two cars A and B but can only purchase one.
We are to find the probability that she will not purchase either car A or car B.
Let, 'C' denotes the event that Marla will purchase car A and 'D' denotes the event that Marla will purchase car 'B'.
Then, according to the given information, we have

Since Marla cannot purchase both the cars, so the events A and B are disjoint.
That is,

Therefore, the probability that Marla will purchase either car A or car B is given by

Hence, the probability that she will not purchase either car A or car B will be

Thus, the required probability is 0.10.