Correct Answer: C

Rationale: To determine the number of trees, reduce the field dimensions by 10 meters (5 meters of space on each side). The effective area is 640 meters 770 meters. Each tree occupies 10 meters 10 meters. Dividing the effective area by the space for each tree gives: (640 770) · (10 10) = 286 trees. Choice A, B, and D are incorrect because they do not consider the reduction in field dimensions and the space required for each tree.

Correct Answer: A

Rationale: The correct answer is A: 28. To find 28% of 100, you multiply 0.28 (the decimal equivalent of 28%) by 100. This calculation results in 28. Therefore, 28% of 100 is 28. Choice B, 20, is incorrect as it represents 20% of 100. Choice C, 25, is incorrect as it represents 25% of 100. Choice D, 30, is incorrect as it represents 30% of 100.

Correct Answer: B

Rationale: To solve the equation 4y - 6 = 14 for y, isolate y by adding 6 to both sides: 4y = 14 + 6 => 4y = 20. Then, divide by 4 to solve for y: y = 20 · 4 = 5. Therefore, the correct answer is 5. Choice A is incorrect as it does not represent the correct solution to the equation. Choice C is incorrect as it is not the solution obtained after correctly solving the equation. Choice D is incorrect as it is not the correct solution to the given equation.

Correct Answer: A

Rationale: When multiplying decimal numbers like 44.44 and 55.55, align them properly and multiply each place accurately. To find the product of 44.44 and 55.55, you get 2,468.64. Therefore, the correct answer is choice A, 2,468.64. Choice B, 2,500.00, is incorrect as it is the result of rounding up. Choice C, 2,450.45, is incorrect as it is not the result of multiplying 44.44 by 55.55. Choice D, 2,470.00, is incorrect as it is not the correct product of 44.44 and 55.55.

Correct Answer: C

Rationale: Reducing the rat's speed by 50% means it will take twice as long to finish the maze. Since the original time is 3 minutes, doubling that gives 6 minutes. Therefore, the total time will be 6 minutes, making the correct answer C. Choice A (3 minutes) is the original time it takes the rat to finish the maze, not the time with the backpack. Choice B (4 minutes) is not correct as reducing the speed by 50% would double the original time. Choice D (1.5 minutes) is incorrect as halving the time is not the effect of reducing the speed by 50%.