In other mapping studies it has been determined that the PKD gene is 10 map units from each of the closest flanking markers. If individual II-7 decided to have a child (the other biological parent is unaffected), and an amniocentesis showed he had transmitted allele A2 to the unborn child, what is the probability that the child has inherited the disease allele?

Give your answer as a decimal number, not a fraction or percentage. One decimal place only please.