Statistical data showed that in $25\%$ of families with two cars the old car is made in Japan, in

$42\%-$ the new car is made in Japan and in $15\%-$ both cars are made in Japan. Among the

families that own two cars, one family is chosen at random.

a$.$ What is the probability that the two cars the family owns are made in Japan, if it has at

least one car made in Japan?

b$.$ What is the probability that the family owns exactly one car made in Japan?