In a class of 25 students, 44% are boys. How many boys are there?
- A. 10 boys
- B. 11 boys
- C. 9 boys
- D. 13 boys
Correct Answer: B
Rationale: To find the number of boys in the class, calculate 44% of 25 students. 44% of 25 is calculated as follows: 0.44 x 25 = 11 boys. Therefore, there are 11 boys in the class. Choice A, 10 boys, is incorrect as it miscalculates the percentage. Choice C, 9 boys, is incorrect as it is less than 11. Choice D, 13 boys, is incorrect as it is greater than the correct calculation.
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What is the result of the expression 4/5 + 6/7?
- A. 1 23/35
- B. 2 5/7
- C. 1 1/7
- D. 1 3/4
Correct Answer: A
Rationale: To add fractions with different denominators, you first need to find a common denominator. In this case, the common denominator for 5 and 7 is 35. Then, convert each fraction to have a denominator of 35. 4/5 becomes 28/35, and 6/7 becomes 30/35. Adding these fractions together gives 58/35, which simplifies to 1 23/35. Therefore, the correct answer is A, 1 23/35. Choice B, 2 5/7, is incorrect because it does not match the correct result. Choice C, 1 1/7, is incorrect as it is not the simplified form of the sum of the fractions. Choice D, 1 3/4, is incorrect as it is a different result and not the sum of 4/5 and 6/7.
Find x if 40:5 = 60:x.
- A. 12
- B. 7
- C. 1
- D. 8
Correct Answer: B
Rationale: To find x in the proportion 40:5 = 60:x, set up the equation: 40/5 = 60/x. Cross-multiply to solve for x: 40x = 60 * 5 => 40x = 300. Divide by 40 to isolate x: x = 300 / 40 = 7.5. However, x should be a whole number since it represents a quantity, so x = 7. Therefore, the correct answer is 7 (B). Choices A, C, and D are incorrect as they do not satisfy the proportion equation.
How many ounces are in 8 & 1/4 pints?
- A. 136 oz
- B. 128 oz
- C. 132 oz
- D. 130 oz
Correct Answer: C
Rationale: To convert 8 1/4 pints to ounces, first convert the mixed number to an improper fraction: 8 1/4 = 33/4. There are 16 ounces in 1 pint. Now, multiply 33/4 by 16 ounces per pint: 33/4 x 16 = 132 ounces. Therefore, the correct answer is 132 oz. Choice A (136 oz) is incorrect because it does not result from the correct conversion. Choice B (128 oz) is incorrect as it is a miscalculation. Choice D (130 oz) is incorrect as well, not derived from the accurate conversion process.
A vitamin's expiration date has passed. It was supposed to contain 500 mg of calcium, but it has lost 325 mg of calcium. How many mg of calcium are left?
- A. 175 mg
- B. 135 mg
- C. 185 mg
- D. 200 mg
Correct Answer: A
Rationale: The correct answer is A: 175 mg. The vitamin originally contained 500 mg of calcium. After losing 325 mg, the remaining amount of calcium is calculated as 500 mg - 325 mg = 175 mg. Choice B (135 mg) is incorrect because the vitamin lost more calcium than that. Choices C (185 mg) and D (200 mg) are incorrect as they do not consider the amount of calcium lost from the original 500 mg.
A set of integers can be classified as positive, negative, or zero. Which of the following statements about multiplying positive and negative integers is ALWAYS true?
- A. The product will always be positive.
- B. The product will always be negative.
- C. The product will depend on the specific positive and negative numbers used.
- D. Positive and negative integers cannot be multiplied.
Correct Answer: B
Rationale: When multiplying a positive integer by a negative integer, the product will always be negative. This is a fundamental rule of arithmetic. The sign of the product is determined by the rule that states a positive number multiplied by a negative number results in a negative number. Therefore, the statement that the product will always be negative is always true when multiplying positive and negative integers. Choice A is incorrect because the product is not always positive when multiplying positive and negative integers. Choice C is incorrect because the product is not dependent on the specific numbers but on the signs of the integers being multiplied. Choice D is incorrect as positive and negative integers can be multiplied.