The phone bill is calculated each month using the equation y = 50x. The cost of the phone bill per month is represented by y and x represents the gigabytes of data used that month. What is the value and interpretation of the slope of this equation?
- A. 75 dollars per day
- B. 75 gigabytes per day
- C. 50 dollars per day
- D. 50 dollars per gigabyte
Correct Answer: D
Rationale: The slope of the equation y = 50x is 50, which means that for each additional gigabyte of data used, the cost increases by 50 dollars. Therefore, the interpretation of the slope is that it represents the cost per gigabyte, making '50 dollars per gigabyte' the correct answer. Choices A, B, and C are incorrect because they do not reflect the relationship between the cost and the amount of data used in the given equation.
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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.
At the beginning of the day, Xavier has 20 apples. At lunch, he meets his sister Emma and gives her half of his apples. After lunch, he stops by his neighbor Jim's house and gives him 6 of his apples. He then uses ¾ of his remaining apples to make an apple pie for dessert at dinner. At the end of the day, how many apples does Xavier have left?
- A. 4
- B. 6
- C. 2
- D. 1
Correct Answer: D
Rationale: Xavier starts with 20 apples. He gives half to Emma, leaving him with 10 apples. After giving 6 more to Jim, he has 4 apples left. Using ¾ of the remaining 4 apples for the pie leaves him with 1 apple at the end of the day. Choice A is incorrect because it doesn't account for the apple pie Xavier made. Choices B and C are incorrect as they don't reflect the correct calculations of apples remaining after each step.
Shawna buys 5.0 gallons of paint. If she uses 2.5 gallons of it on the first day, how much does she have left?
- A. 2.0 gallons
- B. 2.5 gallons
- C. 3.0 gallons
- D. 1.5 gallons
Correct Answer: B
Rationale: To find the remaining paint, subtract the amount used from the total gallons bought. 5.0 - 2.5 = 2.5 gallons. Therefore, Shawna has 2.5 gallons of paint left after using 2.5 gallons on the first day. Choices A, C, and D are incorrect because they do not accurately represent the amount of paint left after using 2.5 gallons.
What is the result of adding 1/6 and 1/2, expressed in reduced form?
- A. 9/7
- B. 1/3
- C. 31/36
- D. 3/5
Correct Answer: B
Rationale: To add 1/6 and 1/2, you need a common denominator, which is 6. So, 1/6 + 3/6 = 4/6. Simplifying 4/6 gives 2/3, which is the correct answer (1/3). Choices A, C, and D are incorrect as they do not represent the correct sum of the fractions 1/6 and 1/2.
A closet is filled with red, blue, and green shirts. If 2/5 of the shirts are green and 1/3 are red, what fraction of the shirts are blue?
- A. 4/15
- B. 1/5
- C. 7/15
- D. 1/2
Correct Answer: C
Rationale: To find the fraction of blue shirts, subtract the fractions of green and red shirts from 1. Green shirts are 2/5 and red shirts are 1/3, which sum up to 11/15. Therefore, blue shirts would be 1 - 11/15 = 4/15. So, the correct answer is 4/15. Choice A (4/15) is incorrect as it represents the overall fraction of green shirts. Choice B (1/5) is incorrect as it does not account for the fractions of green and red shirts. Choice D (1/2) is incorrect as it does not consider the given fractions of green and red shirts.