Evaluate the following expression: -x + y + xy, when x = 4 and y = 2.

Correct Answer: B

Rationale: To evaluate the expression, substitute x = 4 and y = 2 into the expression: -4 + 2 + 4*2. Calculate each term: -4 + 2 = -2, then 4*2 = 8. Adding these results gives -2 + 8 = 6. Therefore, the correct answer is 6. Choice A (2) is incorrect as it does not consider all terms in the expression. Choice C (12) is incorrect as it miscalculates the result by failing to account for the negative sign. Choice D (8) is incorrect as it doesn't consider the negative value of the first term in the expression.

Correct Answer: C

Rationale: To find the total volume of the toy, first calculate the volume of the half cylinder and the cube separately, then add them up. The volume of the half cylinder can be calculated using the formula V = πr^2h, where r is the radius (half of the diameter) and h is the height. Substituting the values, we get V = π(5^2)8 = 200π ≈ 628.32 cubic cm. The volume of the cube is found by V = s^3, where s is the side length. Substituting s = 5, we get V = 5^3 = 125 cubic cm. Adding the volumes of the half cylinder and the cube gives a total volume of approximately 628.32 + 125 = 753.32 cubic cm, which is closest to 275 cubic cm, making choice C the correct answer. Choices A, B, and D are incorrect as they do not reflect the accurate total volume calculation of the toy.

Correct Answer: B

Rationale: To calculate the percentage increase, subtract the original price from the new price, then divide the result by the original price and multiply by 100. In this case, the increase is $10.00 - $9.00 = $1.00. $1.00 divided by $9.00 is approximately 0.1111, which equals 11.11%, making choice B the correct answer. Choice A, 5%, is too low as the increase is more than 5%. Choice C, 20%, and choice D, 25%, are too high, exaggerating the actual increase of $1.00.

Correct Answer: A

Rationale: To find the product of 0.003 and 4.23, multiply the two numbers: 0.003 x 4.23 = 0.01269. Therefore, the correct answer is A, 0.01269. Choice B, 0.01029, is incorrect as it is the result of a different calculation. Choice C, 0.01419, is incorrect because it is not the product of 0.003 and 4.23. Choice D, 0.01329, is also incorrect as it does not represent the correct multiplication result.

Correct Answer: C

Rationale: To convert 5 3/4 to a decimal, we add the whole number part to the fractional part: 5 + 3/4 = 5.75. Rounding 5.75 to the nearest tenth gives us 5.8. Therefore, the correct answer is C. Choice A (5.6) is incorrect because it does not accurately represent 5 3/4. Choice B (5.7) is incorrect as well because it does not reflect the correct conversion. Choice D (6) is incorrect as it does not account for the fractional part of 5 3/4.

Correct Answer: C

Rationale: Given expression: 3a^2 - 2ab + b^2. Substitute the values of a and b: 3(2)^2 - 2(2)(-3) + (-3)^2 = 3(4) + 12 + 9 = 12 + 12 + 9 = 24 + 9 = 33. Therefore, the value of the expression is 33, which corresponds to option C. Options A, B, and D are incorrect as they do not accurately evaluate the expression with the given values of a and b.

Correct Answer: A

Rationale: To convert the fraction 7/8 into a decimal, you divide 7 by 8, which equals 0.875. To express this decimal as a percentage, you multiply it by 100 to get 87.5%. Choices B, C, and D are incorrect because they do not represent the correct conversion of the fraction 7/8 into a decimal and a percent.

Correct Answer: A

Rationale: To find the sum of 1.332 and 0.067, add the two numbers correctly: 1.332 + 0.067 = 1.399. Therefore, the correct answer is A. Choice B (1.4) is incorrect because it rounds down the sum, not considering the precise value. Choice C (1.402) is incorrect as it results from adding 1.332 and 0.070 instead of 0.067. Choice D (1.5) is not the correct sum of the given numbers.

Correct Answer: B

Rationale: To calculate profit, we subtract the total distribution cost from the revenue. Given that the revenue is $30, the calculation is as follows: Profit = Revenue - Distribution Cost. Therefore, Profit = $30 - $10 = $20. Hence, the profit will be $19.60. Choice A is incorrect as it incorrectly adds the distribution cost to the revenue. Choice C is incorrect as it does not consider the distribution cost. Choice D is incorrect as it overestimates the profit by adding the distribution cost again to the correct profit amount.