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: A

Rationale: The Mayan numeric system was a base 20 system, known as vigesimal, as it used base 20 numerals. This system was unique and employed a combination of symbols and positional notation to represent numbers. The Babylonian system was a base 60 system, Roman numerals were based on combinations of letters, and Arabic numerals are in base 10, making choices B, C, and D incorrect.

Correct Answer: C

Rationale: To convert pounds to kilograms, you need to divide the weight in pounds by the conversion factor of 2.2 (1kg = 2.2lbs). 180 pounds / 2.2 = 81.82 kg Rounded to the nearest whole number, the weight of 180 pounds is approximately 82kg. Therefore, the correct answer is 82kg, which is option C. Option B (75kg) is not correct as it is significantly lower than the calculated value. Options A (68kg) and D (90kg) are also incorrect as they do not match the converted weight of 180 pounds.

Correct Answer: B

Rationale: To divide 92 by 11, you get 8 as the whole number part of the quotient. The remainder is 4, so the correct answer is 8 r4. Choice A, 8 r3, is incorrect because the remainder is 4, not 3. Choice C, 8 r7, is incorrect as the remainder cannot be greater than the divisor. Choice D, 9 r1, is incorrect as the whole number part of the quotient is 8, not 9.

Correct Answer: C

Rationale: To simplify the expression -5 - (-6), we can rewrite it as -5 + 6 (since subtracting a negative number is equivalent to adding its positive counterpart). This gives us -5 + 6 = 1. Therefore, the correct answer is 1. Choice A, ½, is incorrect because the subtraction of a negative number results in a positive number. Choices B and D are also incorrect as they do not match the simplified result of -5 - (-6), which is 1.

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: C

Rationale: Since Bruno has 27 stamps from Europe, which is 15 more than from Africa, he must have 27 - 15 = 12 stamps from Africa. Since he also has 18 more stamps from Asia than from Africa, he must have 12 + 18 = 30 stamps from Asia. Therefore, Bruno has 30 Asian stamps. Choice A (12) is the number of stamps Bruno has from Africa, not Asia. Choices B (22) and D (40) are not derived from the correct calculations based on the given information.

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: D

Rationale: The correct answer is D: 16.5. To find the product of 22 and 75, you multiply the two numbers together. Therefore, 22 75 = 1650, which is correctly represented as 16.5 in decimal form. Choices A, B, and C are incorrect as they do not reflect the correct decimal form of the product of 22 and 75. Choice A, 0.00165, is incorrect as it is a very small value that does not match the result of multiplying 22 and 75. Choice B, 0.0165, is also incorrect as it is one tenth of the correct answer. Choice C, 0.165, is incorrect as it is one hundredth of the correct answer. Therefore, the only correct representation in decimal form for the product of 22 and 75 is 16.5.