Correct Answer: A

Rationale: To express the ratio 6:7 as a percentage, we first need to find the total parts in the ratio, which is 6 + 7 = 13. To convert this ratio to a percentage, divide the part you want to find the percentage for by the total parts, then multiply by 100. In this case, to find the percentage for 6 in the ratio 6:7, the calculation would be (6/13) * 100 = 46.15%. Therefore, the correct answer is A, 67%. Choices B, C, and D are incorrect percentages as they do not result from the correct calculation for the given ratio.

Correct Answer: C

Rationale: To convert miles to kilometers, you can use the conversion factor of 1 mile is equal to 1.609 kilometers. Therefore, to find the number of kilometers in 12 miles, you can multiply 12 miles by 1.609 to get 19.2 kilometers. The correct answer is 19.2 kilometers, making choice C the correct option. Choice A (7.5 kilometers) is incorrect because it represents half the correct conversion. Choice B (13.2 kilometers) is incorrect as it does not apply the correct conversion factor. Choice D (22 kilometers) is incorrect and represents an incorrect conversion calculation.

Correct Answer: B

Rationale: Rationale: - Relatively prime numbers are numbers that share no common factors other than 1. - To determine if two numbers are relatively prime, we need to find the greatest common divisor (GCD) of the two numbers. If the GCD is 1, then the numbers are relatively prime. - Let's calculate the GCD for each pair of numbers: A) GCD(12, 16) = 4, not relatively prime B) GCD(15, 17) = 1, relatively prime C) GCD(20, 24) = 4, not relatively prime D) GCD(28, 36) = 4, not relatively prime Therefore, the pair of numbers 15 and 17 are relatively prime because their greatest common divisor is 1, meaning they share no common factors other than 1.

Correct Answer: B

Rationale: Olivia's Bakery gives out one extra cupcake for each dozen sold. For a special order of 180 cupcakes, there would be 180 cupcakes · 12 cupcakes per dozen = 15 dozens. Therefore, the bakery adds 15 extra cupcakes to make a 'baker's dozen' of 13 in all for each dozen, resulting in a total of 15 extra cupcakes added to the special order. The correct answer is 13 (choice B) because the bakery adds one extra cupcake to each dozen, making a 'baker's dozen' of 13.

Correct Answer: B

Rationale: When the real shed roof measures 4 feet by 5 feet, on a 1:10 scale plan, the measurements on the plan would be 1/10 of the real measurements. Therefore, the correct answer is 40 inches by 50 inches since it represents 1/10 of 4 feet by 5 feet. Choice A (80 inches by 100 inches) is incorrect because it is equivalent to the real shed measurements, not the scaled plan. Choice C (4.8 inches by 6 inches) is incorrect as it does not reflect the 1:10 scale reduction. Choice D (4 inches by 5 inches) is incorrect because it does not consider the scale factor of 1:10.