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What is the result of multiplying 3/5 by 5/7?
- A. 3/7
- B. 1
- C. 2
- D. 4
Correct Answer: A
Rationale: To multiply fractions, multiply the numerators together and the denominators together. Multiplying 3/5 by 5/7 gives (3*5)/(5*7) = 15/35. This fraction simplifies to 3/7 by dividing the numerator and denominator by their greatest common factor, which is 5. Therefore, the correct answer is 3/7. Choices B, C, and D are incorrect as they do not result from multiplying 3/5 by 5/7.
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Apply the polynomial identity to rewrite (a + b)².
- A. a² + b²
- B. 2ab
- C. a² + 2ab + b²
- D. a² - 2ab + b²
Correct Answer: C
Rationale: When you see something like (a + b)², it means you're multiplying (a + b) by itself:
(a + b)² = (a + b) (a + b)
To expand this, we use the distributive property (which says you multiply each term in the first bracket by each term in the second bracket):
Multiply the first term in the first bracket (a) by both terms in the second bracket:
a a = a²
a b = ab
Multiply the second term in the first bracket (b) by both terms in the second bracket:
b a = ab
b b = b²
Now, add up all the results from the multiplication:
a² + ab + ab + b²
Since ab + ab is the same as 2ab, we can simplify it to:
a² + 2ab + b²
So, (a + b)² = a² + 2ab + b².
This is known as a basic polynomial identity, and it shows that when you square a binomial (a two-term expression like a + b), you get three terms: the square of the first term (a²), twice the product of the two terms (2ab), and the square of the second term (b²).
Therefore, the correct answer is C (a² + 2ab + b²)
Find the area in square centimeters of a circle with a diameter of 16 centimeters. Use 3.14 for π.
- A. 25.12
- B. 50.24
- C. 100.48
- D. 200.96
Correct Answer: D
Rationale: The formula for the area of a circle is: Area = π x (radius²). Given: Diameter = 16 cm, so Radius = Diameter / 2 = 16 / 2 = 8 cm. Now, calculate the area using π = 3.14: Area = 3.14 x (8²) = 3.14 x 64 = 200.96 cm². The correct answer is D (200.96 cm²) as it correctly calculates the area of the circle. Choices A, B, and C are incorrect as they do not represent the accurate area of the circle based on the given diameter and π value.
What is the perimeter of a square with a side length of 6 cm?
- A. 24 cm
- B. 12 cm
- C. 18 cm
- D. 36 cm
Correct Answer: A
Rationale: The perimeter of a square is calculated by multiplying the side length by 4 since all sides are equal. In this case, the side length is 6 cm, so the perimeter is 4 * 6 = 24 cm. Therefore, choice A, 24 cm, is the correct answer. Choices B, C, and D are incorrect because they do not reflect the correct calculation for the perimeter of a square.
What is the result of multiplying (3/5) by (5/8)?
- A. 3/8
- B. 3/5
- C. 15/40
- D. 3/30
Correct Answer: A
Rationale: To multiply fractions, multiply the numerators together and the denominators together. For (3/5) * (5/8), you get (3*5) / (5*8) = 15 / 40, which simplifies to 3/8. Therefore, the correct answer is A. Choice B (3/5) is incorrect as it is one of the original fractions being multiplied. Choice C (15/40) is the result of the multiplication but not simplified to its lowest terms. Choice D (3/30) is incorrect as the numerator is not the result of multiplying 3 and 5 together.
What is the result of dividing 8 by 4?
- A. 2
- B. 4
- C. 6
- D. 8
Correct Answer: A
Rationale: To find the result of dividing 8 by 4, we divide 8 by 4, which equals 2. Choice B (4) is incorrect because it is the divisor, not the result of the division. Choice C (6) is incorrect as it is not the correct quotient. Choice D (8) is incorrect as it is the dividend, not the result of the division.