Answer:
The probability that both will be Rh-negative out of 99% Rh-positive is 0.01 x 0.01 = 0.0001.
Explanation:
The population contain 99℅ of Rh-positive. This represent almost all of the people.
However, there is still 1℅ chance of having an individual of Rh-negative.
Both of them will have the probability of 1℅ of having Rh-negative(0.01).
Therefore, Pr(Rh-negative AND Rh-negative) = 0.01 x 0.01. The result is approximately equals zero.
The both parents having Rh-negative, will have a dominant Rh-negative blood passed to their children, only recessive Rh-positive of 25℅ chance.
Since the chance of Rh-negative blood passed to their children is 75℅, it is inevitable that their children will be Rh-negative