Correct Answer: B

Rationale: To find the sum of 1/3, 1/4, and 1/6, we need to first find a common denominator. The least common multiple of 3, 4, and 6 is 12. So, we rewrite the fractions with the common denominator: 1/3 = 4/12, 1/4 = 3/12, and 1/6 = 2/12. Adding these fractions together gives us 4/12 + 3/12 + 2/12 = 9/12, which simplifies to 3/4 or 1/2. Therefore, the correct answer is 1/2. Choice A (5/12) is incorrect because it does not represent the sum of the fractions given. Choices C (1/3) and D (1/4) are also incorrect as they are individual fractions and do not represent the sum of the fractions provided.

Correct Answer: A

Rationale: To find the total time taken, add the time for each segment: 1 hour + 1.2 hours + 1.5 hours + 1.6 hours = 5.3 hours. Therefore, it took her 5.3 hours to complete the course. The other choices are incorrect because they do not accurately reflect the cumulative time calculated based on the given information.

Correct Answer: C

Rationale: To convert 9/10 to a decimal, divide 9 by 10: 9 · 10 = 0.9. The correct answer is 0.9. Choice A (0.7) is incorrect as 7/10 is equal to 0.7. Choice B (0.8) is incorrect as 8/10 is equal to 0.8. Choice D (1) is incorrect as 10/10 would be equal to 1.

Correct Answer: B

Rationale: To calculate speed, divide the distance traveled by the time taken: 240 miles · 4 hours = 60 mph. Therefore, the correct answer is B. Choice A (50 mph) is incorrect as it results from an incorrect calculation. Choice C (55 mph) and D (75 mph) are also incorrect because they are not the correct result of dividing 240 miles by 4 hours.

Correct Answer: A

Rationale: To convert a decimal to a fraction, place the decimal value over the place value of the last digit. In this case, 0.25 can be written as 25/100. Simplifying this fraction by dividing both the numerator and denominator by 25 gives 1/4. Therefore, 0.25 expressed as a fraction is 1/4. Choices B, C, and D are incorrect as they represent different fractional values that do not correspond to 0.25.