Question 273 of 480
Simplify the expression \( (3 \times 10^4) \times (2 \times 10^3) \) and express your answer in standard form. What is the result?
- \( 6 \times 10^7 \)
- \( 6 \times 10^8 \)
- \( 6 \times 10^6 \)
- \( 5.5 \times 10^7 \)
Correct Answer:
C
Explanation
To simplify the expression \( (3 \times 10^4) \times (2 \times 10^3) \) and express the answer in standard form, let's break it down step-by-step.
### Step 1: Understand the Components
The expression consists of two parts:
- \( 3 \times 10^4 \): This means 3 multiplied by \( 10^4 \) (which is 10,000).
- \( 2 \times 10^3 \): This means 2 multiplied by \( 10^3 \) (which is 1,000).
### Step 2: Multiply the Coefficients
First, we multiply the numerical coefficients (the numbers in front):
\[
3 \times 2 = 6
\]
### Step 3: Multiply the Powers of Ten
Next, we multiply the powers of ten. When multiplying powers of ten, we add the exponents:
\[
10^4 \times 10^3 = 10^{4+3} = 10^7
\]
### Step 4: Combine the Results
Now, we combine the results from Steps 2 and 3:
\[
(3 \times 10^4) \times (2 \times 10^3) = 6 \times 10^7
\]
### Step 5: Express in Standard Form
The result \( 6 \times 10^7 \) is already in standard form, which is a number between 1 and 10 multiplied by a power of ten.
### Final Answer
Thus, the simplified expression is:
\[
\boxed{6 \times 10^7}
\]
### Explanation of Other Options
Now, let's analyze the other options to understand why they are incorrect:
- **Option B: \( 6 \times 10^8 \)**: This option suggests that we added the exponents incorrectly (4 + 3 = 8 instead of 7). This is a common mistake when multiplying powers of ten.
- **Option C: \( 6 \times 10^6 \)**: This option indicates that the multiplication of the powers of ten was done incorrectly, possibly subtracting instead of adding the exponents (4 - 3 = 1, which is incorrect).
- **Option D: \( 5.5 \times 10^7 \)**: This option suggests a miscalculation of the coefficient. The correct multiplication of the coefficients is \( 3 \times 2 = 6\), not 5.5.
### Common Pitfalls
- **Forgetting to add exponents**: When multiplying powers of ten, always remember to add the exponents.
- **Miscalculating coefficients**: Ensure that you multiply the numerical parts correctly.
- **Not expressing in standard form**: Always check if your final answer is in the correct format (a number between 1 and 10 multiplied by a power of ten).
### Revision Summary
- To multiply numbers in scientific notation, multiply the coefficients and add the exponents of the powers of ten.
- The expression \( (3 \times 10^4) \times (2 \times 10^3) \) simplifies to \( 6 \times 10^7 \).
- Always check that your final answer is in standard form.
- Be cautious of common mistakes, especially with exponent rules and coefficient calculations.