Question

A gallon of milks sells for $3.18 and a quart of milk sells for $0.76. Which item has the better unit price? Justify your answer using two different methods.

Answer 1

Answer:

$Second\ price\ that\ is\ 1\ quart\ milk=\ 0.76\ has\ better\ unit\ price$

Step-by-step explanation:

Use gallon unit:

First Price:

$1\ gallon\ milk=\ 3.18$

Second Price:

$4\ quart=1\ gallon\\\\1\ quart\milk=\ 0.76\\\\4\ quart\ milk=4\times 0.76=\ 3.04\\\\\Rightarrow 1\ gallon\ milk=\ 3.04$

$1\ gallon\ at\ first\ price\ is\ greater\ than\ the\ rate\ of\ 1\ gallon\ at\ second\ price\\\\Hence\ 1\ quart=\ 0.76\ has\ the\ better\ unit\ price.$

Second Method: Use Quart Unit:

First Price:

$1\ gallon=4\ quart\\\\1\ gallon\ milk=\ 3.18\\\\4\ quart\ milk=\ 3.18\\\\1\ quart\ milk=\frac{3.18}{4}=\ 0.795$

Second Price:

$1\ quart\ milk=\ 0.76$

$Second\ price\ that\ is\ 1\ quart\ milk=\ 0.76\ has\ better\ unit\ price$