Which of the following statements demonstrates a negative correlation between two variables?

Correct Answer: C

Rationale: The correct answer is C. This statement demonstrates a negative correlation between two variables as it indicates that as tennis balls age, their bounce tends to decrease. In a negative correlation, as one variable increases, the other tends to decrease. Choices A, B, and D do not illustrate a negative correlation. Choice A describes a positive correlation, as playing baseball more is associated with having more hits. Choice B does not show a correlation but a general observation. Choice D also does not demonstrate a correlation; it simply states that older cars tend to have higher mileage, without implying a relationship between age and mileage.

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.

Correct Answer: B

Rationale: The total cost (T) consists of the initial charge of $40 plus the additional charges based on the number of tablecloths. The correct expression for T is T = 5c + 3.5r + 40. This accounts for the $5 per circular tablecloth (5c), $3.50 per rectangular tablecloth (3.5r), and the initial $40 charge. Choice A is incorrect as it subtracts the initial charge instead of adding it. Choice C is also incorrect as it subtracts the initial charge and has the coefficients in the wrong positions. Choice D adds the initial charge at the end instead of at the beginning, making it incorrect. Therefore, choice B is the correct representation of the total cost to rent tablecloths.

Correct Answer: A

Rationale: An integer is a whole number that can be positive, negative, or zero. It does not include fractions or decimals. Choice B, 'A number with a decimal point,' is incorrect because integers do not have decimal points. Choice C, 'A fraction,' is incorrect because integers are not expressed as ratios of two integers. Choice D, 'A percentage,' is incorrect because integers are not necessarily related to proportions out of 100.

Correct Answer: C

Rationale: A composite number is a positive integer greater than one that has more than two factors. Choice A is incorrect because a number with only two factors is a prime number. Choice B is incorrect as being a fraction does not define a composite number. Choice D is incorrect because a number with exactly two factors is a prime number, not a composite number.