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Simplify the following expression: 5 x 3 · 9 x 4
- A. 5/12
- B. 8/13
- C. 20/27
- D. 47/36
Correct Answer: A
Rationale: To simplify the expression 5 x 3 · 9 x 4, first perform the multiplications and divisions from left to right: 5 x 3 = 15 and 9 x 4 = 36. So, the expression becomes 15 · 36. When dividing fractions, multiply the first fraction by the reciprocal of the second fraction. Hence, 15 · 36 = 15/36. To simplify the fraction further, find the greatest common divisor, which is 3. Divide both the numerator and denominator by 3 to get the final result: 15/36 = 5/12. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not represent the correct simplification of the given expression.
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What is the average length of a human eyelash?
- A. 1 nanometer
- B. 1 centimeter
- C. 1 meter
- D. 1 kilometer
Correct Answer: B
Rationale: The average length of a human eyelash is approximately one centimeter. A nanometer is too small to describe the length of an eyelash. A meter and a kilometer are much longer lengths and not suitable to describe the average human eyelash.
On a highway map, the scale indicates that 1 inch represents 45 miles. If the distance on the map is 3.2 inches, how far is the actual distance?
- A. 45 miles
- B. 54 miles
- C. 112 miles
- D. 144 miles
Correct Answer: D
Rationale: To find the actual distance represented by 3.2 inches on the map, we use the scale of 1 inch representing 45 miles. Setting up the proportion 1 inch = 45 miles, we can calculate the actual distance by multiplying 3.2 inches by 45 miles, which equals 144 miles. Therefore, the correct answer is 144 miles. Choice A (45 miles) is incorrect as it represents the distance for 1 inch on the map, not for 3.2 inches. Choices B (54 miles) and C (112 miles) are incorrect calculations based on a misinterpretation of the scale.
Tom needs to buy ink cartridges and printer paper. Each ink cartridge costs $30. Each ream of paper costs $5. He has $100 to spend. Which of the following inequalities may be used to find the combinations of ink cartridges and printer paper he may purchase?
- A. 30c + 5p ≤ 100
- B. 30c + 5p = 100
- C. 30c + 5p > 100
- D. 30c + 5p < 100
Correct Answer: A
Rationale: The correct inequality is 30c + 5p ≤ 100. This represents the combinations of ink cartridges (c) and printer paper (p) that Tom may purchase, ensuring the total cost is less than or equal to $100. Choice B is incorrect because the total cost should be less than or equal to $100, not equal to. Choices C and D are also incorrect as they indicate the total cost being greater than $100, which is not the case given Tom's budget limit.
Four roommates must use their financial aid checks to pay their living expenses. Each student receives $1000 per month.
One roommate is saving to buy a house, so each month, he puts money aside in a special house savings account. The ratio of his monthly house savings to his rent is 1:3. If he pays $270 per month in rent, how much money does he put into his house savings account each month?
- A. $90
- B. $270
- C. $730
- D. $810
Correct Answer: A
Rationale: The ratio of his savings to his rent is 1:3, which means that for every $3 he pays in rent, he saves $1 for the purchase of a house. To calculate the amount saved, divide $270 by 3: $270 · 3 = $90. Therefore, he puts $90 into his house savings account each month. Choice B, $270, is incorrect because that is the amount he pays in rent, not the amount saved. Choices C and D, $730 and $810, are incorrect as they do not align with the 1:3 ratio described in the question.
During January, Dr. Lewis worked 20 shifts. During February, she worked three times as many shifts as she did during January. During March, she worked half the number of shifts she worked during February. Which equation below describes the number of shifts Dr. Lewis worked in March?
- A. shifts = 20 + 3 + 1/2
- B. shifts = (20)(3)(1/2)
- C. shifts = (20)(3) + 1/2
- D. shifts = 20 + (3)(1/2)
Correct Answer: B
Rationale: During January, Dr. Lewis worked 20 shifts. Shifts for January = 20. During February, she worked three times as many shifts as she did during January. Shifts for February = (20)(3) = 60. During March, she worked half the number of shifts she worked in February. Shifts for March = (60)(1/2) = 30. Therefore, the correct equation to describe the number of shifts Dr. Lewis worked in March is 'shifts = (20)(3)(1/2)', representing the calculation based on the given scenario. Choices A, C, and D do not accurately represent the correct mathematical relationship between the shifts worked in the different months, making them incorrect.