Correct Answer: C

Rationale: To calculate the average of Pernell's scores, add all the scores together and then divide by the number of scores. (81 + 92 + 87 + 89 + 94) = 443. Now, divide 443 by 5: 443 · 5 = 89, which is the average score.

Correct Answer: C

Rationale: To calculate the final dosage, first find 1/5 of 310 mg, which is 62 mg, and subtract it from the original dosage. This gives 310 mg - 62 mg = 248 mg. Then, subtract an additional 20 mg from the result to get the final dosage: 248 mg - 20 mg = 228 mg. Therefore, the patient's final dosage is 228 mg. Choice A (20 mg) is incorrect because it only considers the second reduction of 20 mg and misses the initial reduction by 1/5. Choice B (42 mg) is incorrect as it miscalculates the reduction amounts. Choice D (248 mg) is incorrect as it does not account for the second reduction of 20 mg.

Correct Answer: B

Rationale: To solve the equation 2y + 5 = 25 * 10, start by simplifying the right side: 25 * 10 = 250. Then, subtract 5 from both sides to isolate 2y: 2y = 250 - 5 = 245. Finally, divide by 2 to find the value of y: y = 245 / 2 = 122.5. Therefore, the correct answer is y = 122.5. Choices A, C, and D are incorrect as they do not result from the correct calculation steps.

Correct Answer: B

Rationale: To simplify the expression, first find a common denominator for the fractions. 3/22 can be rewritten as 6/22. Now, the expression becomes 13/22 - 6/22 - 11. Subtracting 6/22 from 13/22 gives 7/22. Therefore, the correct answer is 7/22. Choice A, 19/22, is incorrect as the subtraction was not done properly. Choices C and D are incorrect as they are not part of the expression being simplified.

Correct Answer: A

Rationale: To solve the expression, first calculate the multiplication: (3)(-4) = -12 and (3)(4) = 12. Then, substitute the results back into the expression: (-12) + 12 - 1 = -1. Therefore, the correct answer is A. Choices B, C, and D are incorrect as they do not result from the correct calculations of the given expression.