Subtract and simplify: -5 - (-6) =

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: 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: 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: B

Rationale: 1 liter is equal to 1,000 cubic centimeters. Therefore, when the oxygen flow rate is 4 liters per minute, the calculation is 4 x 1,000 = 4,000 cubic centimeters. Hence, at a flow rate of 4 liters per minute, 4,000 cubic centimeters of oxygen are delivered per minute. Choice A, 400 cubic centimeters, is incorrect because it miscalculates the conversion from liters to cubic centimeters. Choices C and D, 40,000 cubic centimeters and 400,000 cubic centimeters, respectively, are significantly higher than the correct answer due to incorrect conversions or additional errors in calculation.

Correct Answer: D

Rationale: To find 110% of a number, you multiply the number by 1.10. Therefore, 1.10 * 40 = 44. Since 110% of 40 is 44, the correct answer is D. Choice A (60) is the result of finding 150% of 40, not 110%. Choice B (50) is incorrect as it represents 125% of 40. Choice C (55) is not the correct answer as it corresponds to 137.5% of 40.

Correct Answer: B

Rationale: Rationale: 1. Let x be the volume of the 10% solution needed and y be the volume of water needed. 2. The total volume of the final solution is 200ml, so x + y = 200. 3. The concentration of the final solution is 5%, so the amount of salt in the final solution is 0.05 * 200 = 10g. 4. The amount of salt in the 10% solution is 0.1x, and the amount of salt in the water is 0, so the total amount of salt in the final solution is 0.1x. 5. Since the total amount of salt in the final solution is 10g, we have 0.1x = 10. 6. Solving for x, we get x = 100ml. 7. Substituting x =

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: D

Rationale: To convert a fraction to a percentage, you multiply the fraction by 100. To express 4/5 as a percent, you perform the calculation 4/5 * 100 = 80%. Therefore, the correct answer is D, 80%. Choices A, B, and C are incorrect as they do not represent the correct conversion of 4/5 to a percentage.

Correct Answer: C

Rationale: To multiply 25 by 4, you get 100. To express the result in decimal form, you divide by 100. Therefore, the result is 1. Choice A (0.01) is incorrect as it represents 1/100, not the result of 25 4. Choice B (0.1) is incorrect as it represents 1/10. Choice D (10) is incorrect as it is the result before converting it to decimal form.