Answer:
D. 14 cents
Step-by-step explanation:
At 10 feet for $7, that is 70 cents for every foot
At 20 feet for $13, that is 65 cents for every foot
At 50 feet for $28, that is 56 cents for every foot
At 100 feet for $57.50, that is 58 cents (rounded) for every foot
The best deal is 50 feet at 56 cents
The worst deal is 10 feet at 70 cents
So we do 70 - 56 = 14
So the answer is the savings per unit between the best deal and worst deal is 14 cents
