Subtract 20.7 - 13.4.

Correct Answer: C

Rationale: In this subtraction problem, 20.7 - 13.4, the correct answer is C) 7.3. To explain why this is the correct answer, we must consider the place values of each digit. Starting from the right, we subtract 4 from 7, which gives us 3. Then, we subtract 3 from 0, which requires borrowing from the 2, making it 1, and adding 10 to the 0, giving us 10 - 3 = 7. Therefore, the result is 7.3. Now, let's analyze why the other options are incorrect: A) 7.1: This answer is incorrect because it does not account for the correct subtraction of the tenths place. B) 7.5: This answer is incorrect as it incorrectly calculates the difference between 7 and 4. D) 7.6: This option is also incorrect as it does not accurately subtract the tenths and ones places. In an educational context, understanding place value and the concept of borrowing or regrouping is crucial in performing subtraction accurately. This question assesses students' proficiency in subtracting decimals and reinforces the importance of precision in mathematical operations. Mastery of these fundamental arithmetic skills is essential for success in more complex mathematical concepts.

Correct Answer: B

Rationale: There are 1,000 milliliters in a liter. To convert milliliters to liters, you divide by 1,000. Therefore, 8,000 milliliters · 1,000 = 8 liters. This makes option B the correct answer. Option A, 0.8 liters, is incorrect as it is 1/10th of the correct answer. Option C, 0.8 liters (repeated), is also incorrect. Option D, 0.08 liters, is incorrect as it is 1/100th of the correct answer.

Correct Answer: D

Rationale: In this question, the correct answer is D) 140, which represents 70% of 200. To explain why this is the correct choice, we need to understand how to calculate percentages. To find a certain percentage of a number, you multiply the number by the percentage in decimal form. In this case, 70% as a decimal is 0.70. So, 0.70 x 200 = 140. Now, let's examine why the other options are incorrect: A) 100 - This is incorrect because 100 is not 70% of 200. B) 100 - This is a duplicate answer and incorrect for the same reason as option A. C) 200 - This is incorrect because 200 is the total amount, not 70% of it. Educationally, understanding how to calculate percentages is a fundamental math skill. It is important for various real-life applications like calculating discounts, tips, taxes, and understanding data in fields such as science and economics. Mastering percentage calculations enhances numeracy skills and critical thinking, which are essential for success in academic and professional settings. Practicing with questions like these helps reinforce the concept and improves problem-solving abilities.

Correct Answer: C

Rationale: To find the distance traveled, multiply the speed by the time: 60 mph 5 hours = 300 miles. Choice A (360 miles) and Choice D (360 miles) are incorrect as they do not accurately calculate the distance based on the given speed and time. Choice B (240 miles) is also incorrect as it underestimates the distance traveled.

Correct Answer: A

Rationale: In this question, the correct answer is A) 1/6. To understand why this is the correct answer, let's break it down. A six-sided die has 6 possible outcomes (numbers 1 through 6). Since we are looking for the probability of getting a 1 on a six-sided die, there is only 1 favorable outcome (rolling a 1) out of a total of 6 possible outcomes. Therefore, the probability of rolling a 1 is 1 out of 6, which is represented as 1/6. Now, let's analyze why the other options are incorrect: B) 1/4: This is incorrect because the probability of rolling a 1 on a six-sided die is not 1 out of 4. There are 6 sides on a die, so the denominator should be 6, not 4. C) 1/3: This is incorrect because the probability of rolling a 1 on a six-sided die is not 1 out of 3. As explained earlier, there is only 1 favorable outcome out of 6. D) 1/2: This is incorrect because the probability of rolling a 1 on a six-sided die is not 1 out of 2. Again, there is only 1 favorable outcome out of 6, not 2. In an educational context, understanding probability is essential in various fields such as mathematics, statistics, and even in everyday decision-making. Knowing how to calculate probabilities helps in making informed choices and predictions based on data. This question tests the fundamental concept of probability using a simple scenario of rolling a die, reinforcing the importance of understanding basic principles before tackling more complex problems.