6th Grade Math Textbook, Progress

Better Buy

12-9

Which is the better buy? Explain.

1. Drinking Glasses: 2. Corn:
   4 for $1.80 6 ears for 96¢
   6 for $2.40 8 ears for $1.12


2. Detergent: 4. Cereal:
   2 lb box for $1.26 12 oz box for $1.74
   5 lb box for $3.05 15 oz box for $2.04


3. Napkins: 6. Party Favors
   100 count for $.99 10 for $1.50
   145 count for $1.10 30 for $4.45

Think

11¢ is less than 13¢.

A regular-size box of 12-oz dog food sells for $1.50.

A 15-oz jumbo-size box sells for $1.71. Which is the

better buy?

To decide which is the better buy, find the unit price or

unit cost for 1 oz of each type of dog food. Then compare them.

Regular Size Jumbo Size

Let cthe cost of 1 oz. Let nthe cost of 1 oz.



$1

1

.

2

50



1

c

 

$1

1

.

5

71



1

n



12 c$1.50 1 15 n$1.71 1

12 c
 12 $1.50
 12 15 n
 15 $1.71
 15

1 c$.125
$.13 12  n$.114
$.11

Unit cost (cost per oz)

Compare: $.114 $.125

The jumbo size is the better buy.

Its unit cost is less than the unit cost

of the regular-size dog food.

1.3

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