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A mathematics test has a 4:2 ratio of data analysis problems to algebra problems. If the test has 18 algebra problems, how many data analysis problems are on the test?
- A. 24
- B. 28
- C. 36
- D. 38
Correct Answer: C
Rationale: The ratio of 4:2 simplifies to 2:1. This means that for every 2 algebra problems, there is 1 data analysis problem. If there are 18 algebra problems, we can set up a proportion: 2 algebra problems correspond to 1 data analysis problem. Therefore, 18 algebra problems correspond to x data analysis problems. Solving the proportion, x = 18 * 1 / 2 = 9. Hence, there are 9 data analysis problems on the test. Therefore, the total number of data analysis problems on the test is 18 (algebra problems) + 9 (data analysis problems) = 27.
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If a train travels 60 miles per hour for 2 hours, how far does the train travel?
- A. 60 miles
- B. 100 miles
- C. 120 miles
- D. 200 miles
Correct Answer: C
Rationale: To find the distance traveled by the train, we use the formula Distance = Speed x Time. Given that the train travels at 60 miles per hour for 2 hours, the calculation would be 60 miles/hour x 2 hours = 120 miles. Therefore, the correct answer is 120 miles. Choice A (60 miles) is incorrect because it only represents the speed of the train, not the total distance traveled. Choice B (100 miles) is incorrect as it does not account for the full 2 hours of travel. Choice D (200 miles) is incorrect as it overestimates the distance by multiplying the speed by the time incorrectly.
Which of the following describes a graph that represents a proportional relationship?
- A. The graph has a slope of 2,500 and a y-intercept of 250
- B. The graph has a slope of 1,500 and a y-intercept of -150
- C. The graph has a slope of 2,000 and a y-intercept of 0
- D. The graph has a slope of -1,800 and a y-intercept of -100
Correct Answer: C
Rationale: A graph that has a y-intercept of 0 indicates a proportional relationship because the starting value is 0, and no amount is added to or subtracted from the term containing the slope. In this case, choice C is correct as it has a y-intercept of 0, which aligns with the characteristics of a proportional relationship. Choices A, B, and D have non-zero y-intercepts, indicating a starting value other than 0, which does not represent a proportional relationship.
In a study measuring the average hours worked per week by different types of hospital staff (such as nurses and physicians), what are the dependent and independent variables?
- A. The dependent variable is Nurses. The independent variable is Physicians.
- B. The dependent variable is Physicians. The independent variable is Nurses.
- C. The dependent variable is Hospital Staff. The independent variable is Average hours worked per week.
- D. The dependent variable is Average hours worked per week. The independent variable is Hospital Staff.
Correct Answer: D
Rationale: In this study, the dependent variable is the 'Average hours worked per week,' as it relies on the different types of 'Hospital Staff' (the independent variable). The amount of time worked per week varies based on the category of staff being considered. Therefore, the correct choice is D. Choices A and B incorrectly assign the dependent and independent variables to specific staff categories (Nurses and Physicians), which are actually different elements within the study. Choice C incorrectly defines the dependent variable as 'Hospital Staff,' when in fact, it is the 'Average hours worked per week' that is dependent on the type of staff.
Simplify the following expression:
- A. 1 9/16
- B. 1 1/4
- C. 2 1/8
- D. 2
Correct Answer: A
Rationale: To simplify the given expression, start by performing the division first: (2/3) · (4/15) = (2/3) (15/4) = 30/12 = 5/2. Next, multiply this result by 5/8: 5/2 5/8 = 25/16 = 1 9/16. Therefore, the correct answer is A. Choice B (1 1/4) is incorrect as it does not match the simplified result. Choice C (2 1/8) is incorrect as it does not represent the simplified expression. Choice D (2) is incorrect as it does not account for the fractions in the original expression.
In a research study, a researcher collects data on the number of hours spent studying and the grades students received. Which of the following is the dependent variable?
- A. The number of hours spent studying
- B. The grades students received
- C. The subjects students studied
- D. The number of students in the study
Correct Answer: B
Rationale: The correct answer is B: 'The grades students received.' In this scenario, the grades students received are the dependent variable because they are influenced by the number of hours spent studying. The grades are the outcome that is being measured based on the manipulation or observation of the independent variable, which in this case is the number of hours spent studying. Choices A, C, and D are incorrect. The number of hours spent studying is the independent variable being manipulated or observed, the subjects students studied is not directly related to the dependent variable, and the number of students in the study is not the variable being measured or influenced by the independent variable.