Problem 52 - Prealgebra

Question

Sal paid \(\$ 2.79\) for a gallon of milk. Find the cost per quart of milk. F. \(\$ 0.55\) G. \(\$ 0.70\) H. \(\$ 0.93\) J. \(\$1.40\)

Step-by-Step Solution

Answer

The cost per quart is \(\$ 0.70\). Answer option G.

Step 1: Understanding Quarts in a Gallon

A gallon consists of 4 quarts. Therefore, to find the cost per quart, first note that dividing the total cost of one gallon by the number of quarts (4) will give the cost per quart.

Step 2: Formula for Cost Per Quart

The cost per quart can be calculated using the formula: \( \text{Cost per quart} = \frac{\text{Total cost of gallon}}{4} \). Here, the total cost of a gallon is given as \$ 2.79.

Step 3: Calculation of Cost Per Quart

Substitute the given cost of the gallon into the formula: \( \text{Cost per quart} = \frac{2.79}{4} = 0.6975 \).

Step 4: Rounding the Decimal

Round \( 0.6975 \) to two decimal places to find a more convenient value, which is \( 0.70 \).

Step 5: Selecting the Correct Answer

The options provided are F. \(\\( 0.55\), G. \(\\) 0.70\), H. \(\\( 0.93\), and J. \(\\)1.40\). The closest answer to our calculation is G. \(\$0.70\).

Key Concepts

Decimals

Decimals are a way to express fractions in a base ten format. This is super helpful in measurement and currency calculations because it allows for precision and easier manipulation of numbers. In our exercise, the total cost of a gallon is expressed as a decimal: \(2.79\). Here, the digits after the decimal point (\

Rounding Numbers

Rounding numbers is a key skill when working with decimals, especially when you need to simplify numbers for practical use. In this exercise, the calculated cost per quart was \(0.6975\). To make it user-friendly, we round this to two decimal places, resulting in \(0.70\). Number rounding follows basic rules:

• Look at the digit immediately after your designated decimal point (in this case, third decimal place).
• If this digit is 5 or greater, round up the last kept digit by one.
• If it is less than 5, simply remove it without changing the last kept digit.

Rounding makes values easier to read and use, while still keeping them accurate within a reasonable range.

Cost Calculation

Cost calculation is all about determining the value of one unit or portion from a total amount. This is particularly common when you're dealing with bulk purchases or larger quantities. In our exercise, we are asked to find the cost per quart from a gallon of milk. By dividing the total cost of a gallon ($ 2.79) by the number of quarts in a gallon (4), we find that each quart costs about $0.6975. This process helps you understand how much you're spending at a smaller unit level and is useful for budgeting and comparison shopping.

Measurement Units

Measurement units are standard quantities used to quantify physical properties. They are essential for understanding and communicating about items in various forms. For liquid measurements like milk, gallons and quarts are commonly used in the United States. Recognizing that 1 gallon equals 4 quarts is crucial to executing conversions between these units. In the exercise, knowing this conversion allows us to determine how to split the cost ($2.79 for a gallon) down into smaller, more manageable pieces ($0.70 per quart), emphasizing the practical application of unit conversion in real-world scenarios. Understanding sizes and dimensions through measurement units greatly supports daily tasks.