What is the value of x in the ratio and proportion 0.1:10=x:400?

Correct Answer: B

Rationale: To solve the proportion 0.1:10=x:400, first, simplify the left side to 1:100. Then, set up the proportion as 1:100=x:400. Cross multiply to get x = 4. Therefore, the correct answer is B. Choice A (5) is incorrect because it does not match the calculated value of x. Choice C (50) is incorrect as it is not the result of solving the proportion provided. Choice D (25) is incorrect as it does not align with the correct calculation of x.

Correct Answer: D

Rationale: To divide mixed numbers, convert them to improper fractions. 5 & 3/4 = 23/4 and 1/2 = 2/1. So, 23/4 · 2/1 = 23/4 * 1/2 = 23/8 = 2 & 7/8. Therefore, 5 & 3/4 divided by 1/2 reduces to 11 & 1/2. Choices A, B, and C are incorrect because they do not represent the correct result of dividing 5 & 3/4 by 1/2.

Correct Answer: D

Rationale: To find the value of x in the given ratio and proportion, we can set up the equation as 15:2000=x:200. Cross multiply to get x * 2000 = 15 * 200. Simplifying this gives x = 1. Therefore, the correct answer is D, which is 1. Choice A (7), Choice B (0), and Choice C (7,777) are incorrect as they do not match the correct calculation of x.

Correct Answer: B

Rationale: The correct answer is B. When comparing 0.045 and 0.054, 0.045 is less than 0.054. Therefore, the correct relation is 'Less than.' Choice A ('Greater than') is incorrect because 0.045 is not greater than 0.054. Choice C ('Less than or equal to') is incorrect because 0.045 is strictly less than 0.054, not less than or equal to. Choice D ('Equal') is incorrect because 0.045 and 0.054 are not equal.

Correct Answer: B

Rationale: To determine the largest number among the given decimals, compare them. 0.68 is the largest number as it is greater than 0.667, 0.6, and 0.0688. The correct answer is 0.68 because it has the highest value. The other options are smaller: 0.667 is less than 0.68, 0.6 is less than 0.68, and 0.0688 is significantly smaller than 0.68.