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What was the mean time for the women who ran the 200m event at the 2008 Olympic Games (times in seconds: 22.33, 22.50, 22.50, 22.61, 22.71, 22.72, 22.83, 23.22)?
- A. 22.50 sec
- B. 22.66 sec
- C. 22.68 sec
- D. 22.77 sec
Correct Answer: C
Rationale: To find the mean time, you need to add all the times (22.33 + 22.50 + 22.50 + 22.61 + 22.71 + 22.72 + 22.83 + 23.22) and then divide by the total number of times (8). This calculation results in a mean time of 22.68 seconds. Choice A, 22.50 sec, is incorrect because it is the time of one of the runners, not the mean time. Choice B, 22.66 sec, and Choice D, 22.77 sec, are also incorrect as they are not the calculated mean of the given times.
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Dr. Lee observed that 30% of all his patients developed an infection after taking a certain antibiotic. He further noticed that 5% of that 30% required hospitalization to recover from the infection. What percentage of Dr. Lee's patients were hospitalized after taking the antibiotic?
- A. 1.50%
- B. 5%
- C. 15%
- D. 30%
Correct Answer: A
Rationale: To find the percentage of Dr. Lee's patients hospitalized after taking the antibiotic, we need to calculate 30% of 5%. First, convert 30% and 5% to decimals: 30% = 0.30 and 5% = 0.05. Multiply 0.30 by 0.05 to get 0.015. To convert 0.015 to a percentage, multiply by 100, resulting in 1.5%. Therefore, only 1.50% of Dr. Lee's patients were hospitalized after taking the antibiotic. Choice A is correct. Choice B (5%) is incorrect as it represents the percentage of patients who developed an infection and not those hospitalized. Choices C (15%) and D (30%) are also incorrect percentages as they do not accurately reflect the proportion of hospitalized patients in this scenario.
Simplify the following expression: (2/7) · (5/6)
- A. 2/5
- B. 35/15
- C. 5/21
- D. 12/35
Correct Answer: D
Rationale: To divide fractions, you multiply the first fraction by the reciprocal of the second fraction. In this case, (2/7) · (5/6) becomes (2/7) (6/5) = 12/35. Therefore, the correct answer is 12/35. Choice A (2/5), choice B (35/15), and choice C (5/21) are incorrect because they do not correctly simplify the given expression.
Curtis measured the temperature of water in a flask in his science class. The temperature of the water was 35 °C. He carefully heated the flask so that the temperature of the water increased by about 2 °C every 3 minutes. Approximately how much had the temperature of the water increased after 20 minutes?
- A. 10 °C
- B. 13 °C
- C. 15 °C
- D. 35 °C
Correct Answer: B
Rationale: To find the increase in temperature after 20 minutes, calculate how many 3-minute intervals are in 20 minutes (20 · 3 = 6.66, rounding to 7 intervals). Then, multiply the temperature increase per interval (2 °C) by the number of intervals (7 intervals), giving a total increase of 14 °C. Therefore, after 20 minutes, the temperature of the water would have increased by approximately 14 °C. Choice A, 10 °C, is incorrect as it underestimates the total increase. Choice C, 15 °C, is incorrect as it overestimates the total increase. Choice D, 35 °C, is incorrect as it represents the initial temperature of the water, not the increase in temperature.
The number of vacuum cleaners sold by a company per month during Year 1 is listed below: 18, 42, 29, 40, 24, 17, 29, 44, 19, 33, 46, 39. Which of the following is true?
- A. The mean is less than the median
- B. The mode is greater than the median
- C. The mode is less than the mean, median, and range
- D. The mode is equal to the range
Correct Answer: D
Rationale: The mean number of vacuum cleaners sold per month is 31.7, the mode is 29, the median is 31, and the range is 29. The mode being equal to the range is the correct statement. Option A is incorrect because the mean (31.7) is greater than the median (31). Option B is incorrect as the mode (29) is not greater than the median (31). Option C is incorrect since the mode (29) is not less than the mean, median, or range.
A patient requires a 30% decrease in their medication dosage. Their current dosage is 340 mg. What will their dosage be after the decrease?
- A. 70 mg
- B. 238 mg
- C. 270 mg
- D. 340 mg
Correct Answer: B
Rationale: To calculate a 30% decrease of 340 mg, multiply 340 by 0.30 to get 102. Subtracting 102 from 340 gives a new dosage of 238 mg. Choice A (70 mg) is incorrect as it represents a 80% decrease, not 30%. Choice C (270 mg) is incorrect as it does not reflect a decrease but rather the original dosage. Choice D (340 mg) is incorrect as it is the original dosage and not reduced by 30%.