Correct Answer: C

Rationale: To find the value of b in the equation 5b - 4 = 2b + 17, you need to first simplify the equation. By subtracting 2b from both sides of the equation and adding 4 to both sides, you get 3b = 21. Then, dividing both sides of the equation by 3 gives you b = 7. Therefore, the value of b is 7, which corresponds to option C. Choice A (13) is incorrect as it does not match the correct calculation. Choice B (24) is incorrect as it is not the result of the correct algebraic manipulation. Choice D (21) is incorrect as it is not the value of b obtained after solving the equation step by step.

Correct Answer: B

Rationale: To find the median of a set of numbers, first arrange the scores in ascending order: 78, 83, 92, 97. Since there is an even number of scores, we find the median by taking the average of the two middle values. In this case, the middle values are 83 and 92. Calculating (83 + 92) / 2 = 85, we determine that the overall median of Dwayne's scores is 85. Choice A (19) is incorrect as it does not correspond to any value in the given set of scores. Choice C (83) is the median of the original set but not the overall median once arranged. Choice D (87.5) is the average of all scores but not the median.

Correct Answer: A

Rationale: To solve 2 x + 8 = 0 2x+8=0: Subtract 8 from both sides: 2 x = − 8 2x=−8 Divide both sides by 2: x = − 8 2 = − 4 x= 2 −8 ​ =−4 Therefore, the solution is x = − 4 x=−4.

Correct Answer: C

Rationale: To find the solution, first solve the expression inside the parentheses: 25 - 21 = 4. Then, square the result from the parentheses: 4² = 16. Next, perform the multiplication: 4 x 7 = 28. Finally, add the results: 28 + 16 = 44. Therefore, the correct answer is 44. Choice A (512), Choice B (36), and Choice D (22) are incorrect as they do not follow the correct order of operations for solving the given mathematical expression.

Correct Answer: D

Rationale: The scale of 1:100 means that 1 cm² on the floor plan represents 100 cm² in real life. To find the actual area of the room, you need to multiply the area on the floor plan by the square of the scale factor. Since the scale is 1:100, the scale factor is 100. Therefore, 50 cm² on the floor plan represents 50 * 100 = 5000 cm² in real life. Choice A (500 m²) is incorrect as it converts the area from cm² to m² without considering the scale factor. Choice B (50 m²) is incorrect as it does not account for the scale factor. Choice C (5000 cm²) is incorrect as it gives the area on the floor plan, not the actual area.