Simple probabilities W

Not correct. When you are trying to work out probabilities, the usual way is to use a Punnett Square. Put the known genotypes of each parent along each side and combine the alleles in each box. Then count up the options.

Let’s call the mutated allele a and the normal version A. We know that the father is affected, so he is Aa, whereas the mother is not; so she is aa

Aa
AAAAa
AAAAa

From the above, you can see that 2/4 (50%) of the offspring will be AA (unaffected) and 2/4 (50% will be Aa. So the answer was 50%.

Let’s move on