Five gerbils cost p dollars. How many dollars will it cost to buy 1 gerbil? How many dollars will it cost to buy g gerbils? How many gerbils can you purchase for 1 dollar? How many gerbils can you purchase for d dollars?.
5 gerbils = p dollars
1 gerbil = p/5 dollars
g gerbils = pg / 5 dollars
5/p gerbils = 1 dollar
5d/p gerbils = d dollars