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A birdbath has a hemispherical bowl with a diameter of 30cm. What is its volume?
- A. 675 cu cm
- B. 1350 cu cm
- C. 2700 cu cm
- D. 4050 cu cm
Correct Answer: C
Rationale: To find the volume of a hemispherical bowl, we use half the formula for a sphere's volume: (2/3) * π * (radius)^3. Given the diameter is 30cm, the radius is half of that, which is 15cm. Substitute the radius into the formula: (2/3) * π * (15cm)^3 ≈ 2700 cu cm. Therefore, the correct volume is approximately 2700 cu cm. Choices A, B, and D are incorrect as they do not correctly calculate the volume of the hemispherical bowl.
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Which of these percentages equals 1.25?
- A. 1250%
- B. 25%
- C. 50%
- D. 125%
Correct Answer: D
Rationale: To convert 1.25 to a percentage, multiply by 100. Therefore, 1.25 equals 125%. The correct answer is D because 125% is the percentage that represents 1.25. Choices A, B, and C are incorrect. A (1250%) is 10 times greater than the correct answer, B (25%) is 100 times smaller, and C (50%) is 2 times smaller than the correct percentage equivalent of 1.25.
What is the result of adding 5 2/9 and 1 2/9?
- A. 6 4/9
- B. 7 5/9
- C. 7
- D. 5 2/9
Correct Answer: A
Rationale: To add mixed numbers with fractions, first add the whole numbers together: 5 + 1 = 6. Then add the fractions: 2/9 + 2/9 = 4/9. Combining the whole number and the fraction parts gives 6 4/9. Therefore, the correct answer is 6 4/9. Choice B (7 5/9) is incorrect as the fractions were not added correctly. Choice C (7) is incorrect as it does not account for the fractions. Choice D (5 2/9) is one of the original numbers and not the sum of both.
If x = -2 and m = -3, evaluate: xm - 2m
- A. 12
- B. 6
- C. 8
- D. 10
Correct Answer: A
Rationale: Substitute x = -2 and m = -3 into the expression: (-2) * (-3) - 2 * (-3) = 6 + 6 = 12. Therefore, the correct answer is 12. The mistake in the other choices lies in the calculation. Choice B, 6, is the result of adding the two terms instead of subtracting the second term from the first. Choice C, 8, and Choice D, 10, are also incorrect as they do not follow the correct calculation process.
Convert 26°C to Fahrenheit.
- A. 78°F
- B. 72°F
- C. 80°F
- D. 85°F
Correct Answer: A
Rationale: To convert Celsius to Fahrenheit, the formula F = (9/5)C + 32 is used. Substituting 26°C into the formula: F = (9/5)(26) + 32 = 78.8°F, which rounds to 78°F. Therefore, the correct answer is 78°F. Choice B (72°F), Choice C (80°F), and Choice D (85°F) are incorrect as they do not result from the correct conversion calculation.
If 30% of a given number is 18, what is the full number?
- A. 60
- B. 30
- C. 40
- D. 45
Correct Answer: A
Rationale: If 30% of a number is 18, you can find the full number by dividing 18 by 0.30 (the decimal equivalent of 30%). This calculation results in 60. Therefore, the full number is 60. Choice B (30) is the result if 30% of the number itself was calculated, not the full number. Choices C (40) and D (45) are incorrect and do not align with the given information.