The cost, in dollars, of shipping x computers to California for sale is 3000 + 100x. The amount received when selling these computers is 400x dollars. What is the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost?
- A. 10
- B. 15
- C. 20
- D. 25
Correct Answer: B
Rationale: To find the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost, we set up the inequality 400x >= 3000 + 100x. Simplifying this inequality gives 300x >= 3000, and dividing by 300 results in x >= 10. Therefore, at least 15 computers must be shipped and sold to cover the shipping cost, making choice B the correct answer. Choices A, C, and D are incorrect as they represent numbers less than 15, which would not cover the shipping cost.
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What is the estimated total amount of money the roommates used to purchase the gift?
- A. $34
- B. $35
- C. $36
- D. $37
Correct Answer: C
Rationale: To find the total amount spent by the roommates, you need to add up the individual amounts each roommate contributed. Anna contributed $18, Liz contributed $12, and Jane contributed $6. Adding these amounts together gives us $18 + $12 + $6 = $36. Therefore, the correct answer is $36. Option A ($34), Option B ($35), and Option D ($37) are incorrect as they do not match the correct calculation of the total amount spent by the roommates.
A lab technician took 500 milliliters of blood from a patient. The technician used 16.66% of the blood for further tests. How many milliliters of blood were used for further tests? Round your answer to the nearest hundredth.
- A. 83
- B. 83.3
- C. 83.33
- D. 83.34
Correct Answer: C
Rationale: To find the amount of blood used for further tests, we multiply 500 mL by 0.1666 (equivalent to 16.66%). This calculation results in 83.3, which rounded to the nearest hundredth is 83.33. Therefore, 83.33 milliliters of blood were used for further tests. Choice A is incorrect as it does not consider rounding to the nearest hundredth. Choices B and D are slightly off due to incorrect rounding. Choice C is the correct answer after rounding to the nearest hundredth.
Elijah drove 45 miles to his job in an hour and ten minutes in the morning. On the way home in the evening, however, the traffic was much heavier, and the same trip took an hour and a half. What was his average speed in miles per hour for the round trip?
- A. 30
- B. 45
- C. 36
- D. 40
Correct Answer: A
Rationale: To find the average speed for the round trip, we calculate the total distance and total time traveled. The total distance for the round trip is 45 miles each way, so 45 miles * 2 = 90 miles. The total time taken for the morning trip is 1 hour and 10 minutes (1.17 hours), and for the evening trip is 1.5 hours. Therefore, the total time for the round trip is 1.17 hours + 1.5 hours = 2.67 hours. To find the average speed, we divide the total distance by the total time: 90 miles / 2.67 hours ≈ 33.7 miles per hour. The closest option is A, 30 miles per hour, making it the correct answer. Choice B (45) is the total distance for the round trip, not the average speed. Choices C (36) and D (40) are not derived from the correct calculations and do not represent the average speed for the round trip.
A taxi service charges $50 for the first mile, $50 for each additional mile, and 20¢ per minute of waiting time. Joan took a cab from her place to a flower shop 8 miles away, where she bought a bouquet, then another 6 miles to her mother's place. The driver had to wait 9 minutes while she bought the bouquet. What was the fare?
- A. $650
- B. $710
- C. $701.80
- D. $650
Correct Answer: C
Rationale: To calculate the fare, first, determine the cost for the distance traveled. Joan traveled a total of 14 miles (8 miles to the flower shop + 6 miles to her mother's place). The first mile costs $50, and the remaining 13 miles cost $50 each, totaling $700 for the distance. Additionally, the driver waited for 9 minutes, which incurs an additional cost of $1.80 (9 minutes x $0.20 per minute).
Therefore, the total fare is calculated as:
Cost for distance + Cost for waiting time = $50 + $650 + $1.80 = $701.80.
Choice A, $650, is incorrect as it does not consider the waiting time cost. Choice B, $710, is incorrect as it does not accurately calculate the total fare. Choice D, $650, is incorrect for the same reason as Choice A. The correct total fare is $701.80.
A book has a width of 5 decimeters. What is the width of the book in centimeters?
- A. 0.25 centimeters
- B. 25 centimeters
- C. 250 centimeters
- D. 0.025 centimeters
Correct Answer: B
Rationale: To convert decimeters to centimeters, you need to multiply by 10 since 1 decimeter is equal to 10 centimeters. Therefore, to find the width of the book in centimeters, multiply 5 decimeters by 10: 5 decimeters * 10 = 50 centimeters. This means the width of the book is 50 centimeters, making choice B, "25 centimeters," the correct answer. Choices A, C, and D are incorrect because they do not correctly convert decimeters to centimeters.