Question

The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father?

Answer 1

Let the genotype of black hair be BB.
Let the genotype of red hair be bb (recessive gene given).
Therefore the genotype of the mother's hair is bb while the father's hair is BB.

Therefore the child will have black hair since it is dominant but will also contain the recessive red hair trait but will not be expressed i.e. Bb.