Correct Answer: A

Rationale: The correct answer is A: 'Itself.' When any number is raised to the power of 1, it remains unchanged and is equal to itself. This is a fundamental property of exponents. Choice B, 'One,' is incorrect because raising a number to the power of 1 does not result in the answer being 1. Choice C, 'Zero,' is incorrect as any non-zero number raised to the power of 1 is itself, not zero. Choice D, 'The number multiplied by 2,' is incorrect because raising a number to the power of 1 does not involve multiplying it by 2.

Correct Answer: A

Rationale: To convert a mixed number to a decimal, 5 ¼ becomes 5.25. To convert this decimal to a percentage, you multiply it by 100. Therefore, 5.25 100 = 525%. Choice A is correct. Choice B (514%) is incorrect as it does not match the equivalent of 5 ¼. Choice C (5.25%) is the decimal equivalent of 5 ¼, not the percentage. Choice D (5.14%) is a different value and does not represent the percentage equivalent of 5 ¼.

Correct Answer: B

Rationale: To find the sale price after a 15% discount, you calculate 15% of $78, which is $11.70. Subtracting $11.70 from the original price gives $66.30. Since the price is typically rounded, the estimated sale price is $66. Choice A, $12, is too low and does not reflect a 15% discount off $78. Choice C, $22, and choice D, $69, are also incorrect as they do not accurately estimate the sale price after a 15% discount.

Correct Answer: C

Rationale: To find the force needed to stretch the coil 0.1 meters, we can set up a proportion based on the given information. The initial force and stretch are in direct proportion, so we can use this relationship to determine the unknown force. (132 N / 0.07 m) = X / 0.1 m. Cross-multiplying, we get 132 N * 0.1 m / 0.07 m = 188.57 N, which rounds to 188.6 N. Therefore, the correct answer is 188.6 Newtons. Choice A is incorrect as it does not match the calculated answer. Choice B is significantly higher and does not align with the proportional relationship. Choice D is close but does not account for the correct rounding as specified in the question.

Correct Answer: D

Rationale: After one friend eats half of the pizza, there is half left. This remaining half is divided equally among three friends. To find the portion each of the other three friends receives, we divide 1/2 by 3, which equals 1/6. Therefore, each of the other three friends receives 1/6 of the pizza. Choice A, 1/5, is incorrect because the correct portion is 1/6. Choice B, 1/3, is incorrect as each of the three friends receives 1/6. Choice C, 1/4, is incorrect as well since the correct portion is 1/6.