Even if you assume that they are asking about when given a node is a 5 what is the probability it will not have any 5 as a neighbor the result is about 10% whic

Even if you assume that they are asking about when given a node is a 5 what is the probability it will not have any 5 as a neighbor the result is about 10% which is your result without the leading 0.2. That's still not what they got.