Computing Unit Prices to Find the Better Buy

We are asked sometimes to determine which of any two given items is a "better buy". We find the unit price of each item, then comparing the unit prices, we decide that the item with the smaller unit price is the "better buy".

At a book exhibition, vendor A was selpng a 4 books set for $39.20. Vendor B was selpng a 6 books set for $52.98. Books from which vendor were the better buy?

Solution

Step 1:

Unit price of vendor A books = $$frac{39.20}{4}$ = $$9.80$

Unit price of vendor B books = $$frac{52.98}{6}$ = $$8.83$

Step 2:

As $9.80 > $8.83, books from the vendor B were the better buy.

A store had 7 white chairs for $142.94 or 5 black chairs for $101.90.

Which color chair has a lower unit price?

Solution

Step 1:

Unit price of white chairs = $$frac{142.94}{7}$ = $$20.42$

Unit price of black chairs = $$frac{101.90}{5}$ = $$20.38$

Step 2:

As $20.38 < $20.42, black chairs have a lower unit price.