Correct Answer: A

Rationale: In a class of 48 students, with 32 being female, the number of male students is 48 - 32 = 16. To calculate the percentage of male students, divide the number of male students (16) by the total number of students (48) and then multiply by 100 to get the percentage: (16 / 48) * 100 = 33%. Therefore, approximately 33% of the students in the class are male. Choices B, C, and D are incorrect because they do not reflect the correct calculation based on the given information.

Correct Answer: C

Rationale: Rationale: - Since a stop sign has five equal sides, each measuring 25cm, the perimeter can be calculated by adding up the lengths of all five sides. - Perimeter = 25cm + 25cm + 25cm + 25cm + 25cm = 125cm - Therefore, the perimeter of the stop sign is 125cm.

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.

Correct Answer: A

Rationale: To solve the expression 30 1/2 - 13 3/4, first convert the mixed numbers to improper fractions. 30 1/2 is equivalent to 61/2 and 13 3/4 is equivalent to 55/4. Subtracting 55/4 from 61/2 gives 16 3/4, which is the correct answer. Choice B (17) is incorrect as the correct answer is a mixed number, not a whole number. Choice C (15 1/4) is incorrect as it doesn't result from subtracting the given fractions. Choice D (15) is incorrect; the correct answer is greater than 15.

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.