Correct Answer: D

Rationale: After one friend eats a quarter of the burger, 3/4 of the burger remains. Dividing this equally between the other two friends means each receives 3/8 of the whole burger. Therefore, the correct answer is 8-Mar. Choice A (6-Jan), Choice B (4-Jan), and Choice C (4-Mar) are incorrect as they do not accurately represent the portion each of the other two friends receives after one friend consumes a quarter of the burger.

Correct Answer: C

Rationale: The independent variable in a function is the variable that is being manipulated or changed to obtain different values. In the equation f(t) = 4t + 9, the variable 't' is the independent variable. It is the variable that the function f(t) depends on, and changing its value will result in different outputs for the function. The other choices, 'f', '9', and '4', are not the independent variable as they do not represent the variable that is being manipulated to determine the function's output.

Correct Answer: A

Rationale: A common denominator is a shared multiple of the denominators in a set of fractions. It is necessary when adding or subtracting fractions to have a common denominator to ensure that the fractions can be combined accurately. Choice B is incorrect because the common denominator is related to the denominators, not the numerators. Choice C is incorrect because while the common denominator is the same in all fractions being added or subtracted, it is not necessarily a number that is the same in all fractions. Choice D is incorrect because a common denominator is a multiple of the denominators, not a number that divides evenly into both fractions.

Correct Answer: D

Rationale: To convert a fraction to a percentage, you multiply the fraction by 100. In this case, 3/4 * 100% = 75%. Therefore, the correct answer is D. Choice A (57%) is incorrect as it does not represent the fraction 3/4. Choice B (7.50%) is incorrect as it is not the equivalent percentage of 3/4. Choice C (65%) is incorrect as it does not match the percentage value of 3/4.

Correct Answer: B

Rationale: To find 31% of 426, multiply 0.31 by 426. This gives 0.31 426 = 132.06. Therefore, choice B, 132.06, is the correct answer. Choice A, 425.69, is close to the original number but is not the correct answer for the percentage calculation. Choice C, 13.7, is not the correct result for 31% of 426. Choice D, 0.07, is significantly lower than the correct answer and does not represent 31% of 426.