Nokea
What is the domain for the function f(x)=2x+5?
- A. All real numbers
- B. x ≥ 0
- C. x > 0
- D. x ≤ 0
Correct Answer: A
Rationale: The domain of a function represents all possible input values that the function can accept. In this case, the function f(x)=2x+5 is a linear function, and linear functions have a domain of all real numbers. This means that any real number can be substituted for x in the function f(x)=2x+5, making choice A, 'All real numbers,' the correct domain for this function. Choices B, C, and D, restrict the domain unnecessarily by limiting the values of x to specific subsets of real numbers, which does not accurately reflect the nature of the given function.
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How should 0.80 be written as a percent?
- A. 40%
- B. 125%
- C. 90%
- D. 80%
Correct Answer: D
Rationale: To convert a decimal to a percent, move the decimal point two places to the right. Therefore, 0.80 written as a percent is 80%. Choice A is incorrect as it represents 40%. Choice B is incorrect as it represents 125%. Choice C is incorrect as it represents 90%.
Divide 4/3 by 9/13 and reduce the fraction.
- A. 52/27
- B. 51/27
- C. 52/29
- D. 51/29
Correct Answer: A
Rationale: To divide fractions, you multiply the first fraction by the reciprocal of the second fraction. So, (4/3) · (9/13) = (4/3) * (13/9) = 52/27. This fraction is already in its reduced form, making choice A the correct answer. Choices B, C, and D are incorrect as they do not represent the correct result of dividing the fractions 4/3 by 9/13.
Mom's car drove 72 miles in 90 minutes. How fast did she drive in feet per second?
- A. 0.8 feet per second
- B. 48.9 feet per second
- C. 0.009 feet per second
- D. 70.4 feet per second
Correct Answer: B
Rationale: To convert miles per hour to feet per second, you need to convert miles to feet and minutes to seconds. First, convert 72 miles to feet using the conversion factor 1 mile = 5280 feet: 72 miles * 5280 feet/mile = 380160 feet. Then, convert 90 minutes to seconds: 90 minutes * 60 seconds/minute = 5400 seconds. Now, to find the speed in feet per second, divide the distance traveled in feet by the time in seconds: 380160 feet / 5400 seconds = 70.4 feet per second. Therefore, the correct answer is 70.4 feet per second. Choice A, 0.8 feet per second, is incorrect as it is a much lower speed. Choice C, 0.009 feet per second, is also incorrect as it is too low. Choice D, 70.4 feet per second, would be correct if the conversion calculations were accurate, but in this case, it's not the correct answer.
Express as an improper fraction: 8 3/7
- A. 11/7
- B. 21/8
- C. 5/3
- D. 59/7
Correct Answer: D
Rationale: To convert the mixed number 8 3/7 to an improper fraction, multiply the whole number (8) by the denominator (7) and add the numerator (3) to get the numerator of the improper fraction. This gives us (8*7 + 3) / 7 = 59/7. Therefore, the correct answer is 59/7. Choice A (11/7), choice B (21/8), and choice C (5/3) are incorrect because they do not correctly convert the mixed number to an improper fraction.
Round to the nearest tenth: 8.067.
- A. 8.07
- B. 8.1
- C. 8
- D. 8.11
Correct Answer: A
Rationale: When rounding a number to the nearest tenth, you look at the digit in the hundredths place. Since 8.067 has a 6 in the hundredths place, which is equal to or greater than 5, you round the tenths place up by 1. Therefore, rounding 8.067 to the nearest tenth gives 8.07. Choice B (8.1) would be incorrect because 8.067 is closer to 8.1 than to 8, but it's not quite there. Choice C (8) is incorrect as it would be rounding down, and Choice D (8.11) is incorrect as it is rounding to the nearest hundredth, not the nearest tenth.