Correct Answer: A

Rationale: Rational numbers are those that can be written as a simple fraction, including whole numbers and decimals that either terminate or repeat. Irrational numbers, on the other hand, cannot be expressed as fractions. Choice B is incorrect because not all rational numbers necessarily terminate or repeat. Choice C is incorrect as it oversimplifies the concept of rational and irrational numbers by only considering whole numbers and decimals. Choice D is incorrect as it inaccurately defines rational and irrational numbers solely based on decimals terminating or repeating, excluding the broader category of fractions.

Correct Answer: C

Rationale: To calculate a 16% gratuity on a bill of $58.60, you multiply $58.60 by 0.16, which equals $9.376. Rounding this to the nearest cent gives $9.38. Therefore, the estimated gratuity is $9.38. Choice A is incorrect as it does not accurately reflect the calculated amount. Choice B is also incorrect as it does not match the correct calculation. Choice D is incorrect as it is not the nearest estimated value to the calculated amount.

Correct Answer: C

Rationale: Jacob spends 87% of $100, which is $87, leaving her with $13. When she invests the remaining $13 and earns a 75% profit, she gains an additional $9.75. Thus, the total amount she now has is $13 (remaining amount) + $9.75 (profit) = $22.75. Choice A is incorrect as it reflects the remaining amount before investing and earning a profit. Choice B is incorrect as it does not account for the profit earned from the investment. Choice D is incorrect as it only considers the profit amount, not the total sum.

Correct Answer: C

Rationale: To convert a percentage to a decimal, you move the decimal point two places to the left. Therefore, 87.5% as a decimal is 0.875. Choice A (875) is incorrect as it represents the percentage without converting to a decimal. Choice B (8,750) is incorrect as it represents the percentage in whole numbers without decimal conversion. Choice D (8.75) is incorrect as it represents 875% instead of 87.5%.

Correct Answer: C

Rationale: To find out how much sugar should be used when making 0.625 of the recipe, you need to multiply 0.375 (amount required for the full recipe) by 0.625 (proportion of the recipe you want to make). 0.375 * 0.625 = 0.234375. Therefore, you should use 0.234375 cups of sugar, which is equivalent to 0.6 cups. This is the correct answer. Choices A, B, and D are incorrect because they do not correctly calculate the adjusted amount of sugar needed based on the proportion of the recipe being made.