Polydactyly extra digits is a dominant trait caused by gene

Polydactyly (extra digits) is a dominant trait caused by gene P, as opposed to the normal allele p. Cystic fibrosis, c, is a recessive disease as opposed to the normal condition, C. A polydactylous woman, otherwise normal in phenotype, married a healthy normal man. Their four children have the following phenotypes:
Child 1: normal in all respects
Child 2: is polydactylous, otherwise normal
Child 3: has cystic fibrosis, otherwise normal
Child 4: has cystic fibrosis and is polydactylous

a) What is the genotype of the mother
b) What is the genotype of child 3