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A circle has an area of 49π square inches. What is the circumference of the circle in terms of π?
- A. 7Ï€ in
- B. 14Ï€ in
- C. 28Ï€ in
- D. 3.5Ï€ in
Correct Answer: B
Rationale: To find the circumference of a circle in terms of π, we first determine the radius using the formula for the area of a circle, A = πr^2. Given that the area is 49π square inches, we have 49π = πr^2, which simplifies to r = 7. The circumference of a circle is calculated using the formula C = 2πr. Substituting r = 7, we get C = 2π(7) = 14π. Therefore, the circumference of the circle is 14π inches.
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Which of the following relationships represents a positive correlation between two variables?
- A. As the amount of water a plant receives increases,
- B. As the number of hours a person exercises decrease
- C. As a student class attendance decreases, the stude
- D. As the number of mile driven increases, the amount
Correct Answer: A
Rationale: A positive correlation means both variables increase together. As the amount of water a plant receives increases, the plant's health typically improves.
Based on the table showing healthcare spending per capita in a group of African nations, which country experienced the greatest change in dollars spent per capita from 2013 to 2015?
- A. Eritrea 2013 ($56), 2015 ($42)
- B. Nigeria 2013 ($16), 2015 ($21)
- C. Tanzania 2013 ($68), 2015 ($8)
- D. Kenya 2013 ($81), 2015 ($88)
Correct Answer: C
Rationale: To determine the country with the most significant change in healthcare spending per capita, we calculate the difference between the spending in 2015 and 2013 for each country. In the case of Tanzania, the expenditure decreased from $68 in 2013 to $8 in 2015, indicating the largest drop in dollars spent per capita among the options provided. Therefore, the correct answer is C, Tanzania.
If a force of 132 Newtons stretched a coil by 0.007 meters, what force would be needed to stretch the coil by 0.1 meter? Round to the nearest tenth.
- A. 92.4N
- B. 136.0N
- C. 188.6N
- D. 1885.7N
Correct Answer: D
Rationale: To find the force needed to stretch the coil by 0.1 meters, we can use the concept of direct proportionality where the force to stretch remains constant. Setting up a proportion: (132N / 0.007m) = (x / 0.1m). Solving for x, we get x = (132N / 0.007m) * 0.1m = 1885.7N. Therefore, the force required to stretch the coil by 0.1 meters is 1885.7 Newtons.
Solve the equation 2(4x + 3) = 7x + 5 for x. Which of the following is correct?
- A. -1
- B. 1
- C. 11
- D. 2
Correct Answer: A
Rationale: To solve the equation, first distribute the 2 on the left side: 8x + 6 = 7x + 5. Next, move all terms involving x to one side by subtracting 7x from both sides: x + 6 = 5. Then, subtract 6 from both sides to isolate x: x = -1. Therefore, the correct answer is A, -1, as it satisfies the equation 2(4*(-1) + 3) = 7*(-1) + 5. Substituting x = -1 back into the original equation gives 2(4*(-1) + 3) = 7*(-1) + 5, which simplifies to -2 + 6 = -7 + 5, and finally to 4 = -2, proving that -1 is indeed the correct solution.
How should the frequency for each day of the week that students get up after 8 a.m. be best displayed from a class survey?
- A. Bar graph
- B. Scatter plot
- C. Histogram
- D. Pie chart
Correct Answer: A
Rationale: A bar graph is the most appropriate way to display the frequency of students getting up after 8 a.m. on each day of the week. Bar graphs are well-suited for comparing discrete categories, making them ideal for showing the frequency distribution of responses for each day. Each day of the week can be represented on the x-axis, and the frequency of students getting up after 8 a.m. on the y-axis. This allows for a clear visual comparison between the days, making it easy to see which days have a higher frequency of students waking up after 8 a.m. In this case, a bar graph is preferred over other options like scatter plots, histograms, or pie charts, as it provides a simple and effective way to visualize and compare the data across different days of the week.