Spiral Review (CC.6.RP.3c, CC.6.RP.3d, CC.6.EE.1, CC.6.E 3. Sterling silver consists of 92.5% silver and 7.5% copper. What decimal represents the portion of silver in sterling silver? (Lesson 5.2) A 0.925 B 9.25 C 92.5 D 925.0 5. Which of the following should be done first to evaluate 10 + (66 – 62)? (Lesson 7.2)
The Correct Answer and Explanation is:
Let’s break down the two questions:
Question 1: Sterling Silver Composition
Sterling silver is composed of 92.5% silver and 7.5% copper. The question asks for the decimal representation of the portion of silver in sterling silver.
To convert a percentage into a decimal, divide the percentage by 100. So for 92.5%, we do the following calculation:92.5÷100=0.92592.5 \div 100 = 0.92592.5÷100=0.925
So, the decimal that represents the portion of silver in sterling silver is 0.925.
Correct Answer: A. 0.925
Question 2: Evaluating 10 + (66 – 62)
We are given the expression:10+(66−62)10 + (66 – 62)10+(66−62)
To evaluate this expression, we must follow the Order of Operations (also known as PEMDAS or BIDMAS):
- Parentheses: Perform the operation inside the parentheses first. 66−62=466 – 62 = 466−62=4
- Addition: After simplifying inside the parentheses, we add the result to 10. 10+4=1410 + 4 = 1410+4=14
Thus, the first thing to do is to evaluate the expression inside the parentheses.
Correct Answer: First, subtract 66 – 62 inside the parentheses.
In this problem, following the correct order of operations ensures that the evaluation is performed accurately. If we didn’t simplify the parentheses first, we would get an incorrect result.
