How many millimeters are in 4 meters?

Correct Answer: B

Rationale: To convert meters to millimeters, you need to know that there are 1000 millimeters in 1 meter. Therefore, to find out how many millimeters are in 4 meters, you multiply 4 (meters) by 1000 (millimeters per meter), which equals 4000 millimeters. Choice A, 400 mm, is incorrect because it represents 4 decimeters, not 4 meters. Choice C, 40 mm, is incorrect because it represents 4 centimeters, not 4 meters. Choice D, 100 mm, is incorrect because it represents 1 meter, not 4 meters.

Correct Answer: B

Rationale: To convert 1906 to Roman numerals, break it down into components: 1000 (M), 900 (CM), 6 (VI), resulting in MCMVI. Therefore, the correct Roman numeral representation for 1906 is MCMVI. Choice A (MCMIV) is incorrect as it represents 1904. Choice C (MDCCCCVI) is incorrect because it uses the subtractive notation incorrectly, and it's considered nonstandard. Choice D (MCMVII) is incorrect as it represents 1907, not 1906.

Correct Answer: B

Rationale: To convert inches to feet, you divide the number of inches by 12 since there are 12 inches in a foot. Therefore, 72 inches divided by 12 equals 6 feet. The correct answer is 6 feet. Choice A, 12 feet, is incorrect as it is the result if we were converting 144 inches. Choice C, 4 feet, and Choice D, 17 feet, are incorrect conversions and do not correspond to the given measurement of 72 inches.

Correct Answer: B

Rationale: To find the total number of balls needed to make the yellow balls 65% of the total, let x be the total number of balls required. Initially, there are 15 yellow balls. The total number of balls would be 15 + x after adding more yellow balls. The equation to represent this is: (15 + x) / (15 + x) = 0.65 (since the yellow balls need to constitute 65% of the total). Solving this equation gives x = 50, indicating that 50 more yellow balls need to be added to the basket to reach the desired percentage. Choice A, C, and D are incorrect as they do not accurately represent the additional yellow balls needed to achieve the specified percentage.

Correct Answer: A

Rationale: To convert meters to centimeters, you need to multiply the number of meters by 100 since there are 100 centimeters in 1 meter. Therefore, 6 meters is equal to 6 * 100 = 600 cm. Choice A is correct. Choice B (60 cm) is incorrect because it represents the conversion of 0.6 meters to centimeters. Choice C (1000 cm) is incorrect because it represents the conversion of 10 meters to centimeters. Choice D (500 cm) is incorrect because it is halfway between the conversions of 5 meters (500 cm) and 6 meters (600 cm).

Correct Answer: C

Rationale: To divide by a fraction, we can multiply by its reciprocal. Therefore, dividing 32 by 8/9 is the same as multiplying 32 by 9/8, which equals 36. The correct answer is C. Choice A, 4 & 1/9, is incorrect because the result is a whole number. Choice B, 4, is incorrect as it does not consider the fraction. Choice D, 28 & 4/9, is incorrect as it is not the result of dividing 32 by 8/9.

Correct Answer: A

Rationale: The correct answer is 100°C (Choice A). The boiling point of water is the temperature at which it changes from a liquid to a gas. Under normal atmospheric pressure, water boils at 100°C. Choices B, C, and D are incorrect because they do not represent the standard boiling point of water. 98°C, 99°C, and 102°C do not correspond to the temperature at which water boils under normal conditions.

Correct Answer: C

Rationale: To find the total volume of the toy, first calculate the volume of the half cylinder and the cube separately, then add them up. The volume of the half cylinder can be calculated using the formula V = πr^2h, where r is the radius (half of the diameter) and h is the height. Substituting the values, we get V = π(5^2)8 = 200π ≈ 628.32 cubic cm. The volume of the cube is found by V = s^3, where s is the side length. Substituting s = 5, we get V = 5^3 = 125 cubic cm. Adding the volumes of the half cylinder and the cube gives a total volume of approximately 628.32 + 125 = 753.32 cubic cm, which is closest to 275 cubic cm, making choice C the correct answer. Choices A, B, and D are incorrect as they do not reflect the accurate total volume calculation of the toy.

Correct Answer: D

Rationale: A perfect square is a number obtained by squaring an integer. In this case, 16 is a perfect square because it is the result of squaring 4 (4 x 4 = 16). The other answer choices, 10, 12, and 15, are not the product of squaring any whole number, making them incorrect. Therefore, the correct answer is 16, as it is a perfect square.