Question

Nellie is buying bird seed to put in her bird feeders. She uses about 10 pounds of bird seed each week, but has room to store any extra that she purchases.The bird seed comes in 3 different sizes as given below: 3.5 pounds for $2.52 7.5 pounds for $5.40 11 pounds for $7.92 Nellie is trying to be a smart shopper and get the best deal on the bird seed. Which size bag of bird seed should Nellie buy? a. Nellie should buy the 3.5 pound bags because they have the cheapest unit price b. Nellie should buy the 7.5 pound bags because they have the cheapest unit price c. Nellie should buy the 11 pound bags because they have the cheapest unit price. d. Nellie should buy any size she wishes because they all have the same unit price..

Answer 1

The answer is C. Nellie should buy the 11 pound bags they have the cheapest unit price

Answer 2

Given: Nellie has to buy bird seed and the prices are as follows

• 3.5 pounds for $2.52
• 7.5 pounds for $5.40
• 11 pounds for $7.92

To Find: which size bag should Nellie buy (which one would have the cheapest unit price)

Solution: D. Nellie should buy any size because they all have the same unit price.

Explanation:

We begin by finding the unit price, i.e., price per pound for each of the three bags.

This is done by using the Unitary Method. We must divide the price by the volume of the bag to find the price per pound.

• price per unit of the smallest (3.5 pound) bag is $\frac{2.52}{3.5} =0.72 per pound$
• price per unit of the medium (7.5 pound) bag is $\frac{5.40}{7.5} =0.72 per pound$
• price per unit of the biggest (11 pound) bag is $\frac{7.92}{11} =0.72 per pound$