Nokea
Which of the following describes a real-world situation that could be modeled by?
- A. Courtney charges a $12 fee plus $2 per hour to babysit. Kendra charges a $10 fee plus $5 per hour. Write an equation to find the number of hours for which the two charges are equal.
- B. Courtney charges a $2 fee plus $12 per hour to babysit. Kendra charges a $5 fee plus $10 per hour. Write an equation to find the number of hours for which the two charges are equal.
- C. Courtney charges a $12 fee plus $2 to babysit. Kendra charges a $10 fee plus $5 to babysit. Write an equation to find the number of hours for which the two charges are equal.
- D. Courtney charges $10 plus $2 per hour to babysit. Kendra charges $12 plus $5 per hour. Write an equation to find the number of hours for which the two charges are equal.
Correct Answer: A
Rationale: In the given situation, Courtney charges a $12 fee plus $2 per hour to babysit, represented by the equation: 12 + 2h where h is the number of hours. Kendra charges a $10 fee plus $5 per hour, represented by the equation: 10 + 5h. To find the number of hours for which the two charges are equal, we set the two equations equal to each other: 12 + 2h = 10 + 5h. Solving for h gives h = 2. This means that the charges are equal after 2 hours of babysitting. Choice B is incorrect because the fee and hourly rates for Courtney and Kendra are reversed, leading to an incorrect equation. Choices C and D are incorrect as they do not accurately represent the given scenario of fees and hourly rates for babysitting by Courtney and Kendra.
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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 correct answer is $90. If he pays $270 per month in rent and saves a total of $360 per month, he puts $360 - $270 = $90 into his house savings account each month. Choice B ($270) is incorrect as this amount represents the rent paid, not the amount saved. Choices C ($730) and D ($810) are both significantly higher than the correct amount of $90, making them incorrect as they do not align with the given information in the question.
Bob decides to go into business selling lemonade. He buys a wooden stand for $45 and sets it up outside his house. He figures that the cost of lemons, sugar, and paper cups for each glass of lemonade sold will be 10¢. Which of these expressions describes his cost for making g glasses of lemonade?
- A. $45 + $0.1 g
- B. $44.90 g
- C. $44.90 g + 10¢
- D. $90
Correct Answer: A
Rationale: The cost for making g glasses of lemonade includes the initial cost of the stand ($45) plus 10¢ for each glass of lemonade sold. Therefore, the expression that represents the cost for making g glasses of lemonade is $45 + $0.1 g, which matches option A. Choice B, $44.90 g, is incorrect as it does not account for the initial stand cost of $45. Choice C, $44.90 g + 10¢, is incorrect because it does not include the initial stand cost and incorrectly adds an extra 10¢ for every glass. Choice D, $90, is incorrect as it does not consider the variable cost of 10¢ per glass and only represents the initial stand cost.
A commuter survey counts the people riding in cars on a highway in the morning. Each car contains only one man, only one woman, or both one man and one woman. Out of 25 cars, 13 contain a woman and 20 contain a man. How many contain both a man and a woman?
- A. 4
- B. 7
- C. 8
- D. 13
Correct Answer: C
Rationale: Let's denote the number of cars containing only a man as M, only a woman as W, and both a man and a woman as B. Given that there are 25 cars in total, we have:
M + W + B = 25
From the information provided, we know that 13 cars contain a woman (W) and 20 cars contain a man (M). Since each car contains either one man, one woman, or both, the cars that contain both a man and a woman (B) are counted once in each of the M and W categories. Therefore, to find out how many cars contain both a man and a woman, we need to subtract the number of cars that contain only a man and only a woman from the total cars.
M + B = 20 (as 20 cars contain a man)
W + B = 13 (as 13 cars contain a woman)
Solving the above two equations simultaneously, we get:
M = 12, W = 5, B = 8
Therefore, 8 cars contain both a man and a woman. Hence, the correct answer is 8. Choice A, B, and D are incorrect as they do not reflect the correct calculation based on the information provided.
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.
Joshua is taking a test with 30 questions. To qualify for an academic scholarship, he needs to answer at least 80% of the questions correctly. What is the minimum number of questions Joshua must answer correctly to qualify for the scholarship?
- A. 23
- B. 24
- C. 26
- D. 27
Correct Answer: B
Rationale: To qualify for an academic scholarship, Joshua needs to answer at least 80% of the 30 test questions correctly. 80% of 30 is 24, so Joshua must answer at least 24 questions correctly to qualify for the scholarship. Choice A (23) is incorrect as it is below the minimum required percentage. Choices C (26) and D (27) are also incorrect as they exceed the minimum number of questions Joshua needs to answer correctly for the scholarship.