If a child's mother has blonde hair and blue eyes, and the father has black hair and brown eyes, how likely is it that the child would have blonde

it's possible, if the father has those genes in his genotype. So if there are some blonde and blue eyed relatives of your husband. It's possible in 50% chance. Bot blue eyed and blonde child probability is %25. But assuing there are blue eyed and blonde genes in your husband's genes.