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: 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: C

Rationale: To determine the number of items Casey bought for $80, we divide the total amount spent ($80) by the cost per item ($4). The calculation gives us 20, indicating that Casey bought 20 items in total to reach the $80 expenditure ($80 · $4 = 20). Therefore, the correct answer is C, 20. Choices A (12), B (18), and D (24) are incorrect because they do not align with the correct division calculation based on the information provided.

Correct Answer: A

Rationale: To determine the initial amount she had, we subtract the amount spent ($18) from the total amount she had after spending. If she had $1,070 after spending, subtracting $18 gives us $1,052, which was the initial amount. Choices B, C, and D are incorrect as they do not consider the subtraction of the amount spent to find the initial amount.

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.