Correct Answer: A

Rationale: To convert Celsius to Fahrenheit, you can use the formula: (°C 9/5) + 32 = °F. Substituting 15°C into the formula gives us (15 9/5) + 32 = 59°F. Therefore, the approximate temperature on the Fahrenheit scale for 15 degrees Celsius is 59 degrees Fahrenheit. Choice B, C, and D are incorrect as they do not align with the correct conversion formula and calculation.

Correct Answer: C

Rationale: Since Bruno has 27 stamps from Europe, which is 15 more than from Africa, he must have 27 - 15 = 12 stamps from Africa. Since he also has 18 more stamps from Asia than from Africa, he must have 12 + 18 = 30 stamps from Asia. Therefore, Bruno has 30 Asian stamps. Choice A (12) is the number of stamps Bruno has from Africa, not Asia. Choices B (22) and D (40) are not derived from the correct calculations based on the given information.

Correct Answer: B

Rationale: When the real shed roof measures 4 feet by 5 feet, on a 1:10 scale plan, the measurements on the plan would be 1/10 of the real measurements. Therefore, the correct answer is 40 inches by 50 inches since it represents 1/10 of 4 feet by 5 feet. Choice A (80 inches by 100 inches) is incorrect because it is equivalent to the real shed measurements, not the scaled plan. Choice C (4.8 inches by 6 inches) is incorrect as it does not reflect the 1:10 scale reduction. Choice D (4 inches by 5 inches) is incorrect because it does not consider the scale factor of 1:10.

Correct Answer: B

Rationale: 1 liter is equal to 1,000 cubic centimeters. Therefore, when the oxygen flow rate is 4 liters per minute, the calculation is 4 x 1,000 = 4,000 cubic centimeters. Hence, at a flow rate of 4 liters per minute, 4,000 cubic centimeters of oxygen are delivered per minute. Choice A, 400 cubic centimeters, is incorrect because it miscalculates the conversion from liters to cubic centimeters. Choices C and D, 40,000 cubic centimeters and 400,000 cubic centimeters, respectively, are significantly higher than the correct answer due to incorrect conversions or additional errors in calculation.

Correct Answer: A

Rationale: The Mayan numeric system was a base 20 system, known as vigesimal, as it used base 20 numerals. This system was unique and employed a combination of symbols and positional notation to represent numbers. The Babylonian system was a base 60 system, Roman numerals were based on combinations of letters, and Arabic numerals are in base 10, making choices B, C, and D incorrect.