What is the volume of a ball with a diameter of 7 inches?

Correct Answer: A

Rationale: To find the volume of a sphere, the formula V = (4/3)πr³ is used, where r is the radius of the sphere. Given that the diameter of the ball is 7 inches, the radius (r) would be half of the diameter, which is 3.5 inches. Plugging this value into the formula: V = (4/3)π(3.5)³ = (4/3)π(42.875) ≈ 165.7 in³. Therefore, the correct answer is A. Choice B, C, and D are incorrect as they do not accurately represent the volume of the ball with a diameter of 7 inches.

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.

Correct Answer: A

Rationale: The mean is the average of a set of numbers, while the median is the middle value when the numbers are arranged in order. If a set of numbers is skewed to one side with some outliers, the mean can be influenced by these extreme values, causing it to be greater or less than the median. In cases of skewed distribution, the mean typically shifts towards the direction of the outliers, making it less than the median. Choice B is incorrect because the mode, which is the most frequent number in a dataset, may or may not be greater than the median. Choice C is incorrect because the mode can be greater than the mean or median, depending on the data. Choice D is incorrect because the mode, representing the most frequent value, has no direct relationship with the range, which is the difference between the highest and lowest values in a dataset.

Correct Answer: C

Rationale: To calculate the percent decrease in snowfall between the two winters, use the formula: Percent Decrease = ((Initial Value - Final Value) / Initial Value) * 100. In this case, the initial value is 6 inches and the final value is 3 inches. Plug these values into the formula: ((6 - 3) / 6) * 100 = (3 / 6) * 100 = 0.5 * 100 = 50%. Therefore, the correct answer is 50%, which is not listed among the choices provided. Among the given choices, the closest percentage is 41.00%, which corresponds to choice C.

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.

Correct Answer: C

Rationale: Kyle initially had $950 in savings, and one-fifth of that amount would be $190. Since he wishes to donate around $30 to each charity, the total amount he would donate to 8 local charities would be $30 x 8 = $240. This amount is more than one-fifth of $1,000, making the estimate not reasonable. Choice A is incorrect because $190 is the correct one-fifth of $950, not $900. Choice B is incorrect as it compares $190 to a different amount ($1,000) rather than the actual total. Choice D is incorrect as it states that $240 is one-fifth of $1,000, which is inaccurate.

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.

Correct Answer: B

Rationale: If 1 inch on the map represents 60 ft, then for 10 inches on the map, the actual distance would be 10 inches x 60 ft = 600 ft. To convert this to yards, we know that 1 yard equals 3 feet. Therefore, the distance between the two points is 600 ft / 3 ft/yard = 200 yards. Choice A (1800) is incorrect because it incorrectly multiplies by 10 again instead of converting to yards. Choice C (200) is incorrect because it fails to adjust the measurement from feet to yards. Choice D (2) is incorrect as it does not consider the correct conversion factor from feet to yards.

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.