Better buy — Grade 6 Math, what it means and where it is taught
The option with the lower unit price.
Taught in Grade 6 Math.
Where it is taught
Practise this idea
2 questions in the course bank use Better buy, in Proportional Reasoning with Rates, Unit Rates & Better Buys.
Problem 1
A 15-ounce jar costs $4.35. A 24-ounce jar costs $6.72. Which is the better buy?
- The 15-ounce jar
- The 24-ounce jar
- They cost the same per ounce
Worked answer
The 24-ounce jar
15-ounce: 4.35 ÷ 15 = 0.29 per ounce
24-ounce: 6.72 ÷ 24 = 0.28 per ounce
0.28 < 0.29, so the larger jar is cheaper per ounce.
Problem 2
A 12 oz jar is $3.00; an 18 oz jar is $4.05. Which is the better buy?
- The 18 oz jar
- The 12 oz jar
- They are the same
- Cannot tell
Worked answer
The 18 oz jar
0.25 against 0.225 per ounce