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
| A | a | |
| A | AA | Aa |
| A | AA | Aa |
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
