Repeating decimals can be expressed as fractions. Which of the following represents the decimal 0.7777... as a fraction?

Correct Answer: D

Rationale: To express the repeating decimal 0.7777... as a fraction, let x = 0.7777... Multiplying both sides by 10 to shift the decimal point to the right gives: 10x = 7.7777... Subtracting the original equation from the new equation eliminates the repeating decimal: 10x - x = 7.7777... - 0.7777... 9x = 7 x = 7/9. Therefore, the decimal 0.7777... can be expressed as the fraction 7/9. Choices A, B, and C are incorrect as they do not accurately represent the decimal 0.7777... when converted to a fraction.

Correct Answer: D

Rationale: When rolling a standard six-sided die, there are three even numbers (2, 4, 6) out of a total of six possible outcomes (1, 2, 3, 4, 5, 6). The probability of rolling an even number can be calculated as the number of favorable outcomes (3) divided by the total number of outcomes (6), which equals 3/6 = 50%. Therefore, the correct answer is D. Choice A (16%) is incorrect because it does not represent the probability of rolling an even number. Choice B (33%) is incorrect as it does not reflect the correct probability. Choice C (66%) is incorrect as well since it overestimates the probability.

Correct Answer: A

Rationale: To convert liters to milliliters, remember there are 1,000 milliliters in a liter. So, to find how many milliliters are in 5 liters, you multiply 5 (liters) by 1,000 (milliliters per liter), which equals 5,000 milliliters. Choice A is correct as it converts 5 liters to milliliters accurately. Choice B, 50 milliliters, is incorrect as it mistakenly converts liters to milliliters by a factor of 100 instead of 1,000. Choice C, 500 milliliters, is incorrect as it also wrongly converts liters to milliliters by a factor of 10 instead of 1,000. Choice D, 0.5 milliliters, is incorrect as it inaccurately converts 5 liters to 0.5 milliliters, which is not correct.

Correct Answer: A

Rationale: To find the distance traveled, multiply the speed of the train (65 mph) by the time it traveled (1.5 hours): 65 mph 1.5 hours = 97.5 miles. Therefore, the train traveled 97.5 miles. Choice B, 95 miles, is incorrect as it does not account for the correct calculation. Choice C, 100 miles, is incorrect as it is a rounded-up value. Choice D, 100.5 miles, is incorrect as it is a miscalculation.

Correct Answer: D

Rationale: To convert quarts to ounces, you need to know that 1 quart is equal to 32 ounces. Therefore, to find out how many ounces are in 2.5 quarts, you multiply 2.5 by 32, which equals 80 ounces. So, the correct answer is 80 ounces. Choice A (64 ounces) is incorrect as it miscalculates the conversion. Choice B (40 ounces) is incorrect as it does not consider the correct conversion factor. Choice C (32 ounces) is incorrect as it provides the conversion for 1 quart only, not for 2.5 quarts.

Correct Answer: D

Rationale: To express the repeating decimal 0.7777... as a fraction, let x = 0.7777... Multiplying both sides by 10 to shift the decimal point to the right gives: 10x = 7.7777... Subtracting the original equation from the new equation eliminates the repeating decimal: 10x - x = 7.7777... - 0.7777... 9x = 7 x = 7/9. Therefore, the decimal 0.7777... can be expressed as the fraction 7/9. Choices A, B, and C are incorrect as they do not accurately represent the decimal 0.7777... when converted to a fraction.

Correct Answer: A

Rationale: The correct answer is A: 16.67%. When rolling a standard 6-sided die, each face has an equal probability of 1/6. Therefore, the probability of rolling a 5 specifically is 1/6, which is approximately 16.67% when converted to a percentage. Choices B, C, and D are incorrect because they do not reflect the correct probability of rolling a 5 on a standard die.

Correct Answer: B

Rationale: 1 gram is equivalent to 1000 milligrams. The concentration of the medication is 200 milligrams per milliliter. To calculate the volume needed, divide the total amount of medication by the concentration: 1000 mg / 200 mg/mL = 5 mL. Therefore, 5 milliliters of the solution should be drawn up to administer 1 gram of the medication intravenously. Choice A (4 milliliters), Choice C (10 milliliters), and Choice D (20 milliliters) are incorrect because they do not accurately calculate the volume of the solution needed based on the concentration of the medication.

Correct Answer: A

Rationale: To determine the distance traveled by the train, you multiply the speed by the time: 60 mph 2 hours = 120 miles. Therefore, the correct answer is 120 miles. Choice B, 180 miles, is incorrect as it results from multiplying the speed by 3 hours instead of 2. Choice C, 100 miles, is incorrect as it results from multiplying the speed by 1.5 hours. Choice D, 240 miles, is incorrect as it results from multiplying the speed by 4 hours instead of 2.