Your teacher -- or whomever proposed this question -- is trying to deceive you, but we must not let them! There will be 4 different gametes: PR, Pr, Rp, and rp. They are the same for both parents. So, how did I do that? Most of the information in this question is useless. We are asked to find the gametes, and for that, we only need to know the genotype of the parents; this is provided for us. Remember, every gamete produced will have only ONE allele for each gene; this means it will either be P or p and R or r. There are several ways we can do this, but perhaps the easiest to explain here to treat each gene as a "parent" and make a punnet square, so the "father" could be P and p, and the "mother" could be R and r and then punnett square like normal. The result would give you the answer I provided, above: PR, Pr, rP, rp.
Fun fact: I used to teach my students using the "thirsty Thursday" method. You and your friends are going out tonight and you need to pick out something to wear. You have a pair of shorts, pair of pants, a t-shirt, and a tank top. How many different outfits can you make? a)shorts and shirt b) shorts and tank top, c) pants and shirt and d) pants and shirt. Notice the same pattern? It's the same concept.
