We have
1 spice rack ----- 6 shelves
1 shelf ---- 15 spice jar
First, we need to know the number of shelves, so we will divide 2250 between 15
We will need 150 shelves for 2250 spice jars
Then we need to know the number of spice racks, so we need to divide 150 between 6
We will need 25 spice racks for 2250 spice jars