Hannaford sells two sizes of cheerios cereal. The smaller box contains 9 ounces and costs $2.50. The larger box contains 20 ounces and and costs 3.79. What is the
difference in cost in dollars per ounce between the two sizes?

Quantity of cheerios cereal in the smaller box Hannaford sold = 9 ounces

Cost of nine ounces of cheerios cereal = $2.50

Cost of one ounce of cheerios cereal :

Cost of one ounce of cheerios cereal in the smaller box = $0.27

Quantity of cheerios cereal in the larger box Hannaford sold = 20 ounces

Cost of nine ounces of cheerios cereal = $3.79

Cost of one ounce of cheerios cereal :

Cost of one ounce of cheerios cereal in the larger box = $0.18

Difference in their cost per ounce :

Therefore, the difference in cost in dollars per ounce between the two sizes = $0.09