Correct Answer: B

Rationale: If the solution is 60% alcohol, it means that 60% of the solution is alcohol. Therefore, in 200ml of the solution, the amount of alcohol present is: 200ml * 60% = 200ml * 0.60 = 120ml. So, when 200ml of the solution is used, there are 120ml of pure alcohol present. Choice A, 100ml, is incorrect because it does not account for the correct percentage of alcohol in the solution. Choice C, 140ml, and Choice D, 160ml, are incorrect as they overestimate the amount of pure alcohol present in the solution.

Correct Answer: D

Rationale: To convert meters to feet, you can use the conversion factor: 1 meter = 3.28084 feet. Therefore, for 6 meters: 6 3.28084 = 19.684 feet. Rounding to two decimal places, the answer is 19.68 feet. Choice D, 19.68 feet, is the correct conversion. Choice A, 1.83 feet, is incorrect as it seems to be a miscalculation. Choice B, 18.48 feet, is incorrect as it doesn't match the correct conversion. Choice C, 18.8 feet, is also incorrect as it is not the accurate conversion from 6 meters to feet.

Correct Answer: D

Rationale: To calculate the time it takes to travel a certain distance, we can use the formula Time = Distance / Speed. In this case, the helicopter is flying at 80 mph and needs to travel 140 miles. Therefore, Time = 140 miles / 80 mph = 1.75 hours or 1 hour and 45 minutes. So, the correct answer is D. 1 hour 45 minutes. Choices A, B, and C are incorrect as they do not represent the accurate time it takes for the helicopter to cover the 140-mile distance at 80 mph.

Correct Answer: B

Rationale: Rationale: The perimeter of a triangle is the sum of the lengths of its three sides. In this case, the sides of the triangular scarf measure 10cm, 12cm, and 15cm. Therefore, the perimeter is calculated as: Perimeter = 10cm + 12cm + 15cm Perimeter = 37cm Therefore, the correct answer is B) 32cm.

Correct Answer: A

Rationale: The Roman numeric system does not use place value as the Arabic, Decimal, and Binary systems do. In the Roman numeral system, the value of each symbol is independent of its position, unlike in the other systems where the position of a digit affects its value. This unique characteristic of Roman numerals distinguishes them from place-value systems like Arabic, Decimal, and Binary. Therefore, the correct answer is Roman (Choice A). Choices B, C, and D (Arabic, Decimal, and Binary) all utilize place value, where the position of a digit within a number determines its value, unlike Roman numerals.