Caden buys 3.9 pounds of grapes that cost $1.80 per pound. Which expression can be used to find the total cost of the grapes?
The Correct Answer and Explanation is:
The correct expression to find the total cost of the grapes is:
3.9 × 1.80
Explanation
To determine the total cost of an item sold by weight, you multiply the number of pounds (or other units) by the cost per pound. This method applies to many purchases such as produce, meats, or bulk items where the price is given for each unit of weight.
In this problem, Caden is buying 3.9 pounds of grapes. Each pound costs $1.80. To find out how much he needs to pay in total, we use multiplication. This is because each pound costs the same, and he is purchasing multiple pounds. So, the total cost is:
Cost per pound × Number of pounds
Substituting the given values into this formula gives:
1.80 × 3.9
This multiplication represents the repeated addition of $1.80 for each of the 3.9 pounds. Since we are not dealing with whole pounds, multiplication is more precise than adding $1.80 multiple times. It also allows for quick calculation when dealing with decimal values.
You can also reverse the factors in multiplication without changing the result due to the commutative property of multiplication. That means:
3.9 × 1.80 gives the same result as 1.80 × 3.9
Both expressions are mathematically correct and will yield the total price Caden must pay for the grapes.
By calculating the expression:
3.9 × 1.80 = 7.02
So, the total cost of the grapes is $7.02.
Understanding how to build expressions like this helps in everyday situations such as shopping or budgeting. It shows the practical use of multiplication with decimals in real-life problems.
