Correct Answer: C

Rationale: If Uri sold 28 balloons, Tommy sold 28 + 2 = 30 balloons. Since Serena sold 6 fewer balloons than Tommy, she sold 30 - 6 = 24 balloons. Therefore, Serena sold 24 balloons. Choice A, 20 balloons, is incorrect because it doesn't consider the difference in sales between Serena and Tommy. Choice B, 22 balloons, is incorrect as it doesn't account for the correct relation between Tommy and Serena's sales. Choice D, 32 balloons, is incorrect as it doesn't align with the given information about the sales differences.

Correct Answer: C

Rationale: To express the ratio 12:15 as a percentage, you need to find the total parts in the ratio (12 + 15 = 27), then divide one part by the total (12 · 27 = 0.4444). Finally, convert the decimal to a percentage by multiplying by 100 (0.4444 x 100 = 44.44%). Therefore, the ratio 12:15 is equivalent to 44.44% when rounded to two decimal places, which is closest to 75.25% among the answer choices. Choices A, B, and D are incorrect as they do not represent the correct percentage equivalent of the ratio 12:15.

Correct Answer: C

Rationale: To find the miles per gallon Paul's car is averaging, we first need to determine the miles he drives on 9 gallons of gas. Since he drives about 115 miles round trip daily, he covers approximately 115/2 = 57.5 miles one way. If he fills up his gas tank with 9 gallons every other day, he covers 115 miles every 2 days. This means his car is averaging around 57.5 miles per 9 gallons, which equals approximately 6.38 miles per gallon. As he uses 9 gallons every other day, his car averages about 6.38 * 2 = 12.76 miles per gallon. Among the given options, the closest value to this calculation is option C, 25.6 miles per gallon. Choice A is incorrect because it does not accurately reflect the mileage per gallon calculation. Choice B is incorrect as it is not the closest to the calculated value. Choice D is incorrect as it is significantly higher than the calculated mileage per gallon.

Correct Answer: D

Rationale: To multiply 54 by 45, you should multiply the two numbers together: 54 x 45 = 2430. The decimal point is placed after counting the total decimal places in the numbers being multiplied. As there are no decimal places in the numbers 54 and 45, the result is 2430, which is correctly expressed as 24.3 when considering the decimal point placement. Choice A (0.0243) and Choice B (0.243) are incorrect as they represent fractions of 2430. Choice C (2.43) is incorrect as it incorrectly places the decimal point one place before the actual result.

Correct Answer: C

Rationale: To find the sum of 12 + 2 + 312, you simply need to add these numbers together. 12 + 2 = 14, and when you add 312 to 14, you get the correct total of 326. Therefore, the correct answer is C. Choice A (936), choice B (374.4), and choice D (318.24) are incorrect as they do not represent the correct sum of the given numbers.