Correct Answer: B

Rationale: To solve this proportion, set up the equation: 7/42 = 4/x. Cross-multiply to get 7x = 168. Solve for x by dividing both sides by 7, yielding x = 24. Therefore, the correct answer is 24. Choice A (16), Choice C (48), and Choice D (12) are incorrect as they do not satisfy the proportion 7:42 :: 4:x.

Correct Answer: B

Rationale: To convert from Celsius to Fahrenheit, use the formula: F = (C 9/5) + 32. Substituting 50°C: F = (50 9/5) + 32 = 122°F. Therefore, 50°C is approximately 122°F. Choices A, C, and D are incorrect because they do not reflect the accurate conversion of 50°C to Fahrenheit.

Correct Answer: A

Rationale: To find the product of 375 and 2.3, multiply them: 375 2.3 = 862.5. When multiplying by 2.3, it is important to shift the decimal point appropriately after performing the calculation. Choice A, 862.5, is the correct answer. Choice B, 750, is incorrect because it is the result of multiplying 375 by 2. Choice C, 225.75, is incorrect as it appears to be the result of multiplying the numbers in the wrong order. Choice D, 1125, is incorrect as it seems to be the result of multiplying 375 by 3 instead of 2.3.

Correct Answer: B

Rationale: To convert pounds and ounces to grams: 8 pounds = 8 453.59 = 3,628.72 grams. 5 ounces = (5 · 16) 453.59 = 141.75 grams. Total weight = 3,628.72 + 141.75 = 3,629 grams (rounded). Therefore, the infant's weight is approximately 3,629 grams. Choice A, 2268 grams, is incorrect as it does not account for the weight in ounces. Choice C, 3770 grams, is incorrect as it is not the accurate converted weight. Choice D, 3856 grams, is incorrect as it does not consider the conversion of ounces to grams.

Correct Answer: C

Rationale: Rationale: Given formula: HR = (220 - age) * 0.65 Given heart rate: HR = 136.5 Substitute the given heart rate into the formula: 136.5 = (220 - age) * 0.65 Solve for age: 136.5 = 143 - 0.65age 0.65age = 143 - 136.5 0.65age = 6.5 age = 6.5 / 0.65 age = 10 Therefore, the patient's age is 50 (option C).