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Given 15:x=3:8, find x.
- A. x=40
- B. x=20
- C. x=30
- D. x=10
Correct Answer: A
Rationale: To find x, we set up the proportion 15:x = 3:8. Cross multiply to get 15*8 = 3*x, which simplifies to 120 = 3x. Dividing by 3 on both sides gives x = 40. Therefore, x=40 is the correct answer. Choices B, C, and D are incorrect because they do not match the correct calculation. Option B results from incorrectly dividing 15 by 3 instead of multiplying it by 8. Option C comes from dividing 15 by 3, and Option D is the result of dividing 15 by 8 instead of multiplying by 3.
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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 subtracting 7 7/10 from 3 4/5?
- A. 3 9/10
- B. 4
- C. 3
- D. 5
Correct Answer: A
Rationale: To subtract 7 7/10 from 3 4/5, first convert 3 4/5 to have the same denominator as 7 7/10. Converting 4/5 to 8/10, the subtraction becomes 7 7/10 - 3 8/10. Subtracting, 7 - 3 = 4 and 7/10 - 8/10 = -1/10. Therefore, the result is 3 4/5 - 7 7/10 = 3 9/10. Choices B, C, and D are incorrect because they do not reflect the correct subtraction of fractions and whole numbers in this scenario.
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.
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.
What is the result of adding 1/2 + 4/5?
- A. 1 3/10
- B. 1/2/2024
- C. 1 2/5
- D. 1 1/5
Correct Answer: A
Rationale: To add fractions, you need a common denominator. In this case, the common denominator is 10. So, 1/2 + 4/5 = 5/10 + 8/10 = 13/10 = 1 3/10. Therefore, the correct answer is A: 1 3/10. Choice B, 1/2/2024, is incorrect as it does not represent the sum of the fractions given. Choice C, 1 2/5, is incorrect as it does not match the sum calculated. Choice D, 1 1/5, is incorrect as it does not reflect the correct sum of the fractions provided.