Question

Hemophilia a is an x-linked recessive disorder. if a normal man marries a woman who is a carrier, what fraction of their daughters will have hemophilia

Answer 1

Daughters get one X gene from each parent.
If the father is a normal male, he carries only a normal X-gene.
Therefore the daughter will always get a normal gene from the father, and a 50% probability getting an affected gene from the mother, therefore 50% chance of becoming a carrier. The other 50% she will inherit a normal X-gene from each parent, thus a healthy female.

In conclusion, no daughter will have haemophilia from a carrier mother and a normal male.
(however, sons will have a 50% chance of inheriting affected X-gene and hence will have haemophilia).