Rebecca is able to paint 12 pickets on her picket fence in an hour. Her fence is 72 feet long, with 2 pickets per foot. How long will it take her to paint the fence?

Correct Answer: B

Rationale: Rebecca can paint 12 pickets in 1 hour, which means she can paint 12 * 2 = 24 pickets in an hour. Since the fence is 72 feet long with 2 pickets per foot, she needs to paint a total of 72 * 2 = 144 pickets. If she paints 24 pickets per hour, it will take her 144 / 24 = 6 hours to paint the entire fence. Choice A (2.4 hours) is incorrect because it does not consider the total number of pickets on the fence. Choice C (12 hours) is incorrect as it overestimates the time needed based on her painting rate. Choice D (16.4 hours) is incorrect as it miscalculates the time required to paint the entire fence.

Correct Answer: B

Rationale: After spending $6.50 on a sandwich, the man had $3.50 left. Then, after spending $1.80 on a drink, he had $1.70 left. Finally, he spent another $0.75 on a bag of chips. Subtracting $0.75 from $1.70 gives us $0.95, which is the amount of money he had left. Choice A is incorrect because it does not consider the bag of chips he bought. Choice C is incorrect as it miscalculates the remaining amount. Choice D is incorrect as it does not account for the total expenses.

Correct Answer: B

Rationale: Rationale: 1. Let x be the volume of the 10% solution needed and y be the volume of water needed. 2. The total volume of the final solution is 200ml, so x + y = 200. 3. The concentration of the final solution is 5%, so the amount of salt in the final solution is 0.05 * 200 = 10g. 4. The amount of salt in the 10% solution is 0.1x, and the amount of salt in the water is 0, so the total amount of salt in the final solution is 0.1x. 5. Since the total amount of salt in the final solution is 10g, we have 0.1x = 10. 6. Solving for x, we get x = 100ml. 7. Substituting x =

Correct Answer: B

Rationale: 1 liter is equal to 1,000 cubic centimeters. Therefore, when the oxygen flow rate is 4 liters per minute, the calculation is 4 x 1,000 = 4,000 cubic centimeters. Hence, at a flow rate of 4 liters per minute, 4,000 cubic centimeters of oxygen are delivered per minute. Choice A, 400 cubic centimeters, is incorrect because it miscalculates the conversion from liters to cubic centimeters. Choices C and D, 40,000 cubic centimeters and 400,000 cubic centimeters, respectively, are significantly higher than the correct answer due to incorrect conversions or additional errors in calculation.

Correct Answer: A

Rationale: To convert Celsius to Fahrenheit, you can use the formula: (°C 9/5) + 32 = °F. Substituting 15°C into the formula gives us (15 9/5) + 32 = 59°F. Therefore, the approximate temperature on the Fahrenheit scale for 15 degrees Celsius is 59 degrees Fahrenheit. Choice B, C, and D are incorrect as they do not align with the correct conversion formula and calculation.

Correct Answer: B

Rationale: Rebecca can paint 12 pickets in 1 hour, which means she can paint 12 * 2 = 24 pickets in an hour. Since the fence is 72 feet long with 2 pickets per foot, she needs to paint a total of 72 * 2 = 144 pickets. If she paints 24 pickets per hour, it will take her 144 / 24 = 6 hours to paint the entire fence. Choice A (2.4 hours) is incorrect because it does not consider the total number of pickets on the fence. Choice C (12 hours) is incorrect as it overestimates the time needed based on her painting rate. Choice D (16.4 hours) is incorrect as it miscalculates the time required to paint the entire fence.

Correct Answer: C

Rationale: To multiply 25 by 4, you get 100. To express the result in decimal form, you divide by 100. Therefore, the result is 1. Choice A (0.01) is incorrect as it represents 1/100, not the result of 25 4. Choice B (0.1) is incorrect as it represents 1/10. Choice D (10) is incorrect as it is the result before converting it to decimal form.

Correct Answer: D

Rationale: To find 110% of a number, you multiply the number by 1.10. Therefore, 1.10 * 40 = 44. Since 110% of 40 is 44, the correct answer is D. Choice A (60) is the result of finding 150% of 40, not 110%. Choice B (50) is incorrect as it represents 125% of 40. Choice C (55) is not the correct answer as it corresponds to 137.5% of 40.

Correct Answer: A

Rationale: In Roman numerals, 1776 is correctly written as MDCCLXXVI. Here's the breakdown: M (1000) + D (500) + CCC (300) + L (50) + XX (20) + VI (6) = 1776. Therefore, the correct Roman numeral representation of the date 1776 is MDCCLXXVI. Choice A is correct because it follows the correct Roman numeral rules for representing 1776. Choices B, C, and D are incorrect as they do not add up to 1776 according to Roman numeral conventions.