Nokea
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.
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When rounding 245.2678 to the nearest thousandth, which place value would be used to decide whether to round up or round down?
- A. Ten-thousandths
- B. Thousandths
- C. Hundredths
- D. Thousand
Correct Answer: A
Rationale: When rounding a number to the nearest thousandth, you look at the digit in the ten-thousandths place to determine whether to round up or down the digit in the thousandths place. In this case, rounding 245.2678 to the nearest thousandth, the digit in the ten-thousandths place is 6, which is greater than or equal to 5, so you would round up the digit in the thousandths place. Therefore, the correct answer is the ten-thousandths place. Choices B, C, and D are incorrect because they do not directly influence the rounding of the thousandths place in this scenario.
What is the value of 0.0523 expressed as a fraction?
- A. 523/10000
- B. 523/1000
- C. 523/100
- D. 523/10
Correct Answer: A
Rationale: To convert a decimal to a fraction, place the decimal value over the place value of the last digit. In this case, 0.0523 can be expressed as 523/10000 since the last digit is in the ten-thousandths place. Choice A is correct. Choices B, C, and D are incorrect because they represent different decimal values and do not match the correct conversion of 0.0523.
What is the perimeter of a rectangle with a length of 7 cm and a width of 3 cm?
- A. 21 cm
- B. 10 cm
- C. 14 cm
- D. 20 cm
Correct Answer: D
Rationale: To find the perimeter of a rectangle, you add the lengths of all its sides. In this case, the formula for the perimeter of a rectangle is 2*(length + width). Substituting the given values, we get: 2*(7 cm + 3 cm) = 2*(10 cm) = 20 cm. Therefore, the correct answer is 20 cm. Choice A (21 cm) is incorrect because it is the sum of the individual sides rather than the perimeter. Choice B (10 cm) is incorrect because it only represents one side of the rectangle. Choice C (14 cm) is incorrect as it is not the total perimeter of the rectangle.
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.
What is the domain for the function y = 1/x?
- A. All real numbers except 0
- B. x > 0
- C. x = 0
- D. x = 1
Correct Answer: A
Rationale: The domain of a function consists of all possible input values that produce a valid output. In the case of y = 1/x, the function is undefined when x = 0 because division by zero is not defined in mathematics. Therefore, the correct domain for y = 1/x is all real numbers except 0 (Choice A). Choice B, x > 0, is incorrect because it excludes the value x = 0. Choice C, x = 0, is also incorrect as x = 0 is not a valid part of the domain due to the function being undefined at this point. Choice D, x = 1, is unrelated to the domain of the function and does not represent the set of valid input values for y = 1/x.