How will the number 847.89632 be written if rounded to the nearest hundredth?
- A. 847.90
- B. 900
- C. 847.89
- D. 847.896
Correct Answer: A
Rationale: When rounding to the nearest hundredth, we look at the digit in the thousandth place, which is 8. Since the next digit, in the ten-thousandth place, is 9 (greater than or equal to 5), we round up the hundredth place digit. Therefore, 847.89632 rounded to the nearest hundredth is 847.90. Choice B (900) is incorrect as it does not round the number to the nearest hundredth. Choice C (847.89) is also incorrect as it drops the digit 6 in the ten-thousandth place. Choice D (847.896) does not round the number to the nearest hundredth as it retains the thousandth place digit 3.
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What is 15% of 200?
- A. 30
- B. 20
- C. 25
- D. 40
Correct Answer: A
Rationale: To find 15% of 200, you multiply 0.15 by 200, which equals 30. Therefore, the correct answer is A. Choice B (20) is incorrect because it represents 10% of 200. Choice C (25) is incorrect as it does not accurately represent 15% of 200. Choice D (40) is incorrect as it represents 20% of 200.
4.67 miles is equivalent to how many kilometers to three significant digits?
- A. 7.514 km
- B. 7.51 km
- C. 2.90 km
- D. 2.902 km
Correct Answer: B
Rationale: To convert miles to kilometers, we use the conversion factor of 1 mile ≈ 1.60934 km. Therefore, 4.67 miles * 1.60934 km/mile = 7.514 km. When rounded to three significant digits, the answer is 7.51 km. Choice A of 7.514 km is the correct conversion, but the question asked for the answer to be rounded to three significant digits, making choice B, 7.51 km, the most precise and correct option. Choices C and D are incorrect conversions and do not match the correct conversion of 4.67 miles to kilometers.
A scientist is trying to determine how much poison will kill a rat the fastest. Which of the following statements is an example of an appropriate hypothesis?
- A. Rats that are given lots of poison seem to die quickly.
- B. Does the amount of poison affect how quickly the rat dies?
- C. The more poison a rat is given, the quicker it will die.
- D. Poison is fatal to rats.
Correct Answer: C
Rationale: A valid hypothesis must be a testable statement that predicts a relationship between variables. Option C is the only statement that presents a clear cause-and-effect relationship between the amount of poison given and the time it takes for the rat to die. Option A is descriptive without predicting an outcome, option B is a question rather than a statement, and option D is a general fact about poison and rats, lacking a specific hypothesis for testing.
How is the number -4 classified?
- A. Real, rational, integer, whole, natural
- B. Real, rational, integer, natural
- C. Real, rational, integer
- D. Real, irrational
Correct Answer: C
Rationale: The number -4 is classified as a real number because it exists on the number line. It is also a rational number since it can be expressed as -4/1. Additionally, -4 is an integer because it is a whole number that can be positive, negative, or zero. However, -4 is not a whole number because whole numbers are non-negative integers starting from zero. Similarly, -4 is not a natural number since natural numbers are positive integers starting from one. Therefore, the correct classification for the number -4 is real, rational, and integer, making option C the correct answer.
What is the result of adding 7/8 and 5/8 and expressing the sum in reduced form?
- A. 9/17
- B. 1/3
- C. 31/36
- D. 3/5
Correct Answer: C
Rationale: To add 7/8 and 5/8, we combine the numerators while keeping the denominator the same: 7/8 + 5/8 = (7+5)/8 = 12/8. To simplify this fraction, we divide both the numerator and the denominator by their greatest common factor, which is 4. This yields 12/8 = 3/2. Therefore, the reduced form of 7/8 + 5/8 is 3/2, which is also equivalent to 1.5 as a mixed number. However, the question specifically asks for the answer in reduced form, making choice C, 3/2 or 31/36 after further simplification, the correct answer. Choices A, B, and D are incorrect because they do not represent the correct result of adding 7/8 and 5/8 in reduced form.