Correct Answer: D

Rationale: On a 1:100 scale drawing, each centimeter represents one meter. The area of the room in the scale drawing is 30 cm², which means the actual area is 30 m². Choice A (30,000 cm²) is incorrect as it doesn't account for the scale conversion. Choice B (300 m²) is incorrect because it multiplies the scale area directly by 10,000, which is not the correct conversion. Choice C (3,000 m²) is also incorrect as it applies the scale factor incorrectly.

Correct Answer: C

Rationale: Erma receives a 25% discount on the $44 sweater, which amounts to a $11 discount. Therefore, she pays $44 - $11 = $33 for this sweater. Adding this discounted price to the $50 sweater, Erma will spend a total of $50 + $33 = $83. Choice A, $79, is incorrect because it does not include the correct calculation for the discounted sweater. Choice B, $81, is incorrect as it does not consider the discounts on both sweaters. Choice D, $85, is incorrect since it overestimates the total amount Erma will spend.

Correct Answer: B

Rationale: To find the increase in temperature after 20 minutes, calculate how many 3-minute intervals are in 20 minutes (20 · 3 = 6.66, rounding to 7 intervals). Then, multiply the temperature increase per interval (2 °C) by the number of intervals (7 intervals), giving a total increase of 14 °C. Therefore, after 20 minutes, the temperature of the water would have increased by approximately 14 °C. Choice A, 10 °C, is incorrect as it underestimates the total increase. Choice C, 15 °C, is incorrect as it overestimates the total increase. Choice D, 35 °C, is incorrect as it represents the initial temperature of the water, not the increase in temperature.

Correct Answer: D

Rationale: To solve the equation for x, follow these steps: 2x - 7 = 3. Add 7 to both sides to isolate 2x, resulting in 2x = 10. Then, divide by 2 on both sides to find x, which gives x = 5. Therefore, the correct answer is x = 5. Choices A, B, and C are incorrect because they do not accurately solve the equation.

Correct Answer: A

Rationale: To represent 'Four more than a number, x', we write x + 4. This is equal to '2 less than 1/3 of another number, y', which translates to 1/3y - 2. Therefore, the correct equation is x + 4 = (1/3)y - 2. Choice B is incorrect as it incorrectly combines the values of x and y. Choice C is incorrect as it doesn't properly relate x and y with the given conditions. Choice D is incorrect as it doesn't correctly represent the relationship between x and y according to the given statement.