15\25 + 42\52 = ?

Correct Answer: A

Rationale: 15\25 + 42\52 simplifies to 1 3\10.

Correct Answer: A

Rationale: To find the value of x, set up the proportion 7/9 = x/63. Cross multiply to get 7*63 = 9*x. This simplifies to 441 = 9x. Divide both sides by 9 to solve for x, giving x = 49. Therefore, the correct answer is A. Choice B (x = 39), Choice C (x = 50), and Choice D (x = 59) are incorrect as they do not match the correct calculation based on the proportion set up.

Correct Answer: A

Rationale: To find the total area covered by the stones, multiply the number of stones by the area each stone covers: 1,200 stones * 0.75 sq ft = 900 sq ft. Therefore, the stones will cover 900 sq ft, which is closest to 800 sq ft among the answer choices A, B, C, and D. The correct answer is A, 800 sq ft. Choices B, C, and D are incorrect as they do not result from the correct calculation of multiplying the number of stones by the area each stone covers.

Correct Answer: A

Rationale: To solve the equation 3x - 5 = 10, start by isolating x. Add 5 to both sides of the equation to get 3x = 15. Then, divide by 3 on both sides to find x = 5. Therefore, the correct answer is x = 5. Choice B, x = 10, is incorrect because adding 5 to 10 does not yield 10. Choice C, x = 15, is incorrect as adding 5 to 15 does not equal 10. Choice D, x = 20, is incorrect because adding 5 to 20 does not result in 10.

Correct Answer: A

Rationale: To subtract 2 5/8 from 7/8, first, convert 7/8 to an equivalent fraction with the same denominator as 2 5/8, which is 8. 7/8 equals 1 whole and 1/8. Subtracting 1 whole from 2 whole results in 1 whole, and subtracting 1/8 from 5/8 gives 4/8 or 1/2. Therefore, the answer is 1 1/2, which simplifies to 1 3/4. Choice B, 2, is incorrect as it doesn't represent the correct result of the subtraction. Choice C, 1, is incorrect as it doesn't account for the fractional part of the answer. Choice D, 2 & 1/2, is incorrect as it doesn't match the calculated result of 1 3/4.

Correct Answer: D

Rationale: To find the value of x, cross multiply in the ratio 18:x=10:300. This gives 18 * 300 = 10 * x. Solving for x, x = 540. Therefore, the correct answer is D. Choice A (16), Choice B (180), and Choice C (30) are incorrect because they do not satisfy the proportion equation 18:x=10:300 when cross multiplied.

Correct Answer: B

Rationale: The opposite of a number is the number that, when added to it, results in zero. In this case, the opposite of -3 is a number that, when added to -3, gives 0. Therefore, the opposite of -3 is 3, as -3 + 3 = 0. Choice A, -6, is incorrect because -3 + (-6) = -9, not zero. Choice C, 0, is the additive inverse of 0, not -3. Choice D, 6, is also incorrect as -3 + 6 = 3, not zero.

Correct Answer: A

Rationale: To convert Fahrenheit to Celsius, you can use the formula: °C = (°F - 32) x 5/9. Plugging in the value, °C = (104 - 32) x 5/9 = 72 x 5/9 = 40°C. Therefore, 104°F is equal to 40°C. Choice A is correct. Choice B is incorrect as it is not the result of the conversion. Choice C is incorrect as it is not the result of the conversion. Choice D is incorrect as it is not the result of the conversion.

Correct Answer: A

Rationale: To add fractions, you need a common denominator. In this case, the common denominator is 57 * 75 = 4275. So, (47*75 + 65*57) / 4275 = (3525 + 3705) / 4275 = 7230 / 4275. Simplifying this fraction gives 1 23/35. Choice B: 2 1/3 is incorrect as the correct result is not a mixed number. Choice C: 1 2/3 is incorrect as it does not match the simplified result of the expression. Choice D: 1 5/6 is incorrect as it is a different value from the correct result obtained by adding the fractions.