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Solve for x: 2x - 7 = 3
- A. x = 4
- B. x = 3
- C. x = -2
- D. x = 5
Correct Answer: D
Rationale: To solve the equation for x, follow these steps: 2x - 7 = 3. Add 7 to both sides to isolate 2x, resulting in 2x = 10. Then, divide by 2 on both sides to find x, which gives x = 5. Therefore, the correct answer is x = 5. Choices A, B, and C are incorrect because they do not accurately solve the equation.
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While at the local ice skating rink, Cora went around the rink 27 times in total. She slipped and fell 20 of the 27 times she skated around the rink. What approximate percentage of the times around the rink did Cora not slip and fall?
- A. 37%
- B. 74%
- C. 26%
- D. 15%
Correct Answer: C
Rationale: To find the approximate percentage of the times Cora did not slip and fall, subtract the times she fell (20) from the total times around the rink (27), which gives 7. Then, divide the number of times she did not slip and fall (7) by the total times around the rink (27) and multiply by 100 to get the percentage. So, 7 divided by 27 equals 0.259, which rounds to approximately 26%. Therefore, the correct answer is 26%. Choice A (37%) is incorrect because it does not reflect the calculation based on the given information. Choice B (74%) is incorrect as it is not the result of the correct calculation. Choice D (15%) is incorrect as it does not match the calculated percentage based on the scenario provided.
Which of the following algebraic equations correctly represents the sentence 'Four more than a number, x, is 2 less than 1/3 of another number, y'?
- A. x + 4 = (1/3)y - 2
- B. 4x = 2 - (1/3)y
- C. 4 - x = 2 + (1/3)y
- D. x + 4 = 2 - (1/3)y
Correct Answer: A
Rationale: To represent 'Four more than a number, x', we write x + 4. This is equal to '2 less than 1/3 of another number, y', which translates to 1/3y - 2. Therefore, the correct equation is x + 4 = (1/3)y - 2. Choice B is incorrect as it incorrectly combines the values of x and y. Choice C is incorrect as it doesn't properly relate x and y with the given conditions. Choice D is incorrect as it doesn't correctly represent the relationship between x and y according to the given statement.
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.
The first midwife uses 2/5 of her monthly contribution to pay for rent and utilities. She saves half of the remainder for incidental expenditures, and uses the rest of the money to purchase medical supplies. How much money does she spend on medical supplies each month?
- A. $600
- B. $800
- C. $1,000
- D. $1,200
Correct Answer: A
Rationale: The first midwife contributes $2000. She spends $800 on rent and utilities. After paying for rent and utilities, $1200 remains. Half of this amount, which is $600, is saved for incidental expenditures. Therefore, the first midwife spends the remaining $600 on purchasing medical supplies each month. Choice A, $600, is the correct answer. Choices B, C, and D are incorrect as they do not accurately reflect the amount spent on medical supplies as calculated in the given scenario.
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.