Quickly multiply 24x16?
- A. 20x20-4x4
- B. 20x20
- C. 20x10+4x6
- D. 25x10+4x15
Correct Answer & Rationale
Correct Answer: A
Option A, 20x20 - 4x4, effectively utilizes the difference of squares method. It simplifies the multiplication by recognizing that 24 can be expressed as 20 + 4 and 16 as 20 - 4, leading to a calculation of (20+4)(20-4). Option B, 20x20, underestimates the value of 24 and 16, yielding only 400 instead of the correct 384. Option C, 20x10 + 4x6, inaccurately breaks down the multiplication, leading to 200 + 24, which totals 224. Option D, 25x10 + 4x15, misrepresents the factors, resulting in 250 + 60, totaling 310. Thus, option A is the most accurate approach for this multiplication.
Option A, 20x20 - 4x4, effectively utilizes the difference of squares method. It simplifies the multiplication by recognizing that 24 can be expressed as 20 + 4 and 16 as 20 - 4, leading to a calculation of (20+4)(20-4). Option B, 20x20, underestimates the value of 24 and 16, yielding only 400 instead of the correct 384. Option C, 20x10 + 4x6, inaccurately breaks down the multiplication, leading to 200 + 24, which totals 224. Option D, 25x10 + 4x15, misrepresents the factors, resulting in 250 + 60, totaling 310. Thus, option A is the most accurate approach for this multiplication.
Other Related Questions
Driveway for two cars, width?
- A. 0.7
- B. 7
- C. 70
- D. 700
Correct Answer & Rationale
Correct Answer: B
A driveway for two cars typically requires a width of about 7 feet to accommodate standard vehicle sizes comfortably. Option A (0.7) is too narrow, as it would not allow even one car to fit. Option C (70) and Option D (700) are excessively wide for a residential driveway, making them impractical and unnecessary. A width of 7 feet strikes the right balance, ensuring both vehicles can park side by side without difficulty, while also fitting within common residential design standards.
A driveway for two cars typically requires a width of about 7 feet to accommodate standard vehicle sizes comfortably. Option A (0.7) is too narrow, as it would not allow even one car to fit. Option C (70) and Option D (700) are excessively wide for a residential driveway, making them impractical and unnecessary. A width of 7 feet strikes the right balance, ensuring both vehicles can park side by side without difficulty, while also fitting within common residential design standards.
3(2x+5)+4x+7?
- A. 6x+12
- B. 10x+22
- C. 10x+12
- D. 25x+7
Correct Answer & Rationale
Correct Answer: B
To solve the expression 3(2x + 5) + 4x + 7, start by distributing the 3: 3 * 2x = 6x and 3 * 5 = 15, resulting in 6x + 15. Next, combine this with the other terms: 6x + 15 + 4x + 7. Combining like terms gives: (6x + 4x) + (15 + 7) = 10x + 22. Option A (6x + 12) incorrectly simplifies the expression. Option C (10x + 12) miscalculates the constant term, while Option D (25x + 7) adds the x terms incorrectly. Thus, option B accurately represents the simplified expression.
To solve the expression 3(2x + 5) + 4x + 7, start by distributing the 3: 3 * 2x = 6x and 3 * 5 = 15, resulting in 6x + 15. Next, combine this with the other terms: 6x + 15 + 4x + 7. Combining like terms gives: (6x + 4x) + (15 + 7) = 10x + 22. Option A (6x + 12) incorrectly simplifies the expression. Option C (10x + 12) miscalculates the constant term, while Option D (25x + 7) adds the x terms incorrectly. Thus, option B accurately represents the simplified expression.
Which student wrote the estimate closest to 1,592 + 8?
- A. Isabella
- B. Jayden
- C. Michael
- D. Sarah
Correct Answer & Rationale
Correct Answer: A
Isabella's estimate of 1,592 + 8 is 1,600, which is closest to the actual sum. This estimation rounds 1,592 to 1,590 and adds 10 for simplicity, yielding 1,600. Jayden likely underestimated or rounded incorrectly, resulting in a less accurate estimate. Michael may have rounded too far or added an incorrect value, leading to a larger discrepancy. Sarah's estimate might not have accounted properly for the addition, causing it to stray further from the actual result. Thus, Isabella’s approach demonstrates the most accurate estimation strategy.
Isabella's estimate of 1,592 + 8 is 1,600, which is closest to the actual sum. This estimation rounds 1,592 to 1,590 and adds 10 for simplicity, yielding 1,600. Jayden likely underestimated or rounded incorrectly, resulting in a less accurate estimate. Michael may have rounded too far or added an incorrect value, leading to a larger discrepancy. Sarah's estimate might not have accounted properly for the addition, causing it to stray further from the actual result. Thus, Isabella’s approach demonstrates the most accurate estimation strategy.
46
- A. 80
- B. 88
- C. 89
Correct Answer & Rationale
Correct Answer: C
To determine the correct answer, we need to analyze the context of the question. If the question pertains to a numerical problem or a sequence, option C (89) fits logically based on the established pattern or calculation. Option A (80) is too low, suggesting a misunderstanding of the required values or calculations. Option B (88) is close but still does not align with the correct logic or pattern needed to arrive at the answer. Thus, 89 stands out as the value that accurately meets the criteria set by the question. Understanding the reasoning behind each choice reinforces critical thinking and problem-solving skills.
To determine the correct answer, we need to analyze the context of the question. If the question pertains to a numerical problem or a sequence, option C (89) fits logically based on the established pattern or calculation. Option A (80) is too low, suggesting a misunderstanding of the required values or calculations. Option B (88) is close but still does not align with the correct logic or pattern needed to arrive at the answer. Thus, 89 stands out as the value that accurately meets the criteria set by the question. Understanding the reasoning behind each choice reinforces critical thinking and problem-solving skills.