If you cross the genotype Pp with pp, the possible genotypes in offspring are

Pp and pp

the genotypic ratio is 2Pp: 2 pp

Explanation:

When doing the cross you can consider the possibility of the outcome through a punnet square or probability.

A punnet square is the best option to do so, however.

Make a grade with four boxes and place one allele of one genotype over each box like this

            P                                        p

Add the letters of the other genotype next to the boxes.

            P                                        p

p                                  

p                                  

Now put one allele in the box, like you are multiplying the letters

            P                                        p

p           Pp                   pp

p                Pp              pp

Now you have done a punnet square