How many quarts are in a gallon?

Correct Answer: D

Rationale: The correct answer is D, which is 4 quarts in a gallon. In the US customary system, there are 4 quarts in a gallon. Choice A is incorrect as it represents the equivalent of a quart, not a gallon. Choice B and C are incorrect as they are smaller quantities than a gallon and do not match the conversion of quarts to a gallon.

Correct Answer: A

Rationale: The sum of two odd numbers is even because odd numbers have a difference of 1 and adding them results in a multiple of 2. The sum of two even numbers is even because even numbers are multiples of 2. When an odd number and an even number are added, the result is odd because the even number contributes an extra 1 to the sum, making it an odd number. Therefore, the correct answer is A. Choices B, C, and D have incorrect combinations of the sum of odd and even numbers.

Correct Answer: A

Rationale: In mathematics, "is" signifies equality, meaning that the values or expressions on both sides of the equation are the same. For example, in the equation 2+2=4, the phrase "2 + 2 is 4" indicates that the sum of 2 and 2 equals 4. "Multiply" refers to the operation of combining two numbers to obtain a product. For instance, in the expression 34, we multiply 3 by 4 to get 12. "Subtract" means to take one number away from another, resulting in a difference. For example, in 5−2, we subtract 2 from 5 to get 3. "Add" refers to the operation of combining two numbers to get a sum. For example, in 2+3, we add 2 and 3 to get 5.

Correct Answer: A

Rationale: The correct formula for the area of a circle is A = πr², where π is a mathematical constant approximately equal to 3.14159 and r is the radius of the circle. Choice B, A = 2πr, represents the circumference of a circle, not the area. Choice C, A = πd, incorrectly uses the diameter (d) instead of the radius in the formula for area. Choice D, A = 2πd, is also related to the circumference of the circle, not the area. Therefore, option A is the only correct formula for calculating the area of a circle.

Correct Answer: A

Rationale: The correct way to find the radius of a circle when given the diameter is by dividing the diameter by 2 to get the radius (Radius = Diameter · 2). When given the circumference, you need to divide the circumference by 2π to find the radius (Radius = Circumference · 2π). Choice A provides the accurate formulas for finding the radius in both scenarios. Choices B, C, and D present incorrect formulas that do not align with the correct calculations for determining the radius of a circle based on the given information.