Correct Answer: A

Rationale: If 3 bags of chips cost $4.50, then the cost per bag is $4.50/3 = $1.50. To buy five bags, John would need to pay 5 bags * $1.50 = $7.50. Therefore, it will cost John $7.50 to buy five bags of chips. The other choices are incorrect because they do not accurately calculate the total cost based on the given information.

Correct Answer: A

Rationale: To convert a decimal to a percentage, you move the decimal point two places to the right and add a percentage sign. Therefore, 0.608 as a percent is 60.8%. The correct answer is A. Choice B (68%) is incorrect because it represents the percentage for a different decimal value. Choice C (0%) is incorrect as it represents 0 as a percentage, not 0.608. Choice D (6%) is incorrect as it also represents a different decimal value, not 0.608.

Correct Answer: B

Rationale: 1 milliliter is approximately equal to 0.2 teaspoons. To find out how many teaspoons are in 0.8 milliliters, we can set up a proportion: 0.8 milliliters * 0.2 teaspoons/1 milliliter = 0.16 teaspoons. Since 0.16 teaspoons is not one of the answer choices, we need to convert it to a more practical measurement. The closest option is 0.4 teaspoons, making it the correct answer. Choice A, 0.2 teaspoons, is incorrect because 0.8 milliliters is more than that. Choices C and D, 0.6 teaspoons and 0.8 teaspoons, respectively, are also incorrect based on the conversion factor of 1 milliliter to 0.2 teaspoons.

Correct Answer: B

Rationale: There are 1,000 milliliters in 1 liter. The prefix 'milli-' means one-thousandth, so when converting from liters to milliliters, you multiply by 1,000. Therefore, the correct answer is 1,000 mL. Choice A (100 mL) is incorrect as it represents one-tenth of the correct conversion. Choice C (500 mL) is incorrect as it is half of the correct conversion. Choice D (50 mL) is incorrect as it is one-twentieth of the correct conversion.

Correct Answer: A

Rationale: To add fractions, find a common denominator, which in this case is 40. Convert each fraction to have the common denominator: 7/8 = 35/40, 9/10 = 36/40, and 6/5 = 48/40. Add these fractions to get 119/40. Simplify this improper fraction to a mixed number, which is 3 & 39/40. Choice B and C are incorrect as they do not represent the sum of the fractions. Choice D is incorrect; the whole number part should be 3, not 2.