What is the sum of 3/7, 4/7, and 2/7?
- A. 7/7
- B. 9/7
- C. 6/7
- D. 7/7
Correct Answer: B
Rationale: To find the sum of fractions with the same denominator, add the numerators. Here, 3/7 + 4/7 + 2/7 = (3 + 4 + 2)/7 = 9/7. Therefore, the correct answer is 9/7. Choice A (7/7) is incorrect as the sum is not 7/7. Choice C (6/7) is incorrect as the sum is not 6/7. Choice D (7/7) is incorrect as the sum is not 7/7.
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If a marathon runner burns 2276 calories in 21.4 miles, what is their rate of calories burned per mile?
- A. 107.5
- B. 106.4
- C. 105.6
- D. 109.3
Correct Answer: B
Rationale: To find the rate of calories burned per mile, divide the total calories burned by the total miles run: 2276 · 21.4 ≈ 106.4 calories per mile. This calculation gives the average number of calories burned for each mile of the marathon. Choice A, 107.5, is incorrect as it does not match the precise calculation result. Choices C and D are also incorrect as they are not the accurate rate of calories burned per mile based on the given data.
Multiply: 3/4 1/3.
- A. 1/4
- B. 1/3
- C. 3/5
- D. 3/8
Correct Answer: A
Rationale: To multiply fractions, multiply the numerators together and the denominators together. In this case, 3/4 1/3 = (3 1) / (4 3) = 3/12 = 1/4. Therefore, the correct answer is A: 1/4. Choices B (1/3), C (3/5), and D (3/8) are incorrect because they do not result from the correct multiplication of the given fractions.
Repeating decimals can be expressed as fractions. Which of the following represents the decimal 0.7777... as a fraction?
- A. 77/1000
- B. 70/99
- C. 777/900
- D. 7/9
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.
Solve: 8x = x^2.
- A. 6
- B. 4
- C. 16
- D. 14
Correct Answer: C
Rationale: To solve the equation 8x = x^2, rearrange it to x^2 - 8x = 0. Factor out an x to get x(x - 8) = 0. Set each factor to zero to find the solutions: x = 0 or x = 8. Therefore, x = 16 is the correct answer because x = 0 is not in the answer choices, and x = 8 is a distraction meant to confuse. Thus, choice C, 16, is the correct solution to the equation.
A circular bandage has a diameter of 6cm. What is the area covered by the bandage (area of a circle = πr^2)?
- A. 9π cm^2
- B. 18π cm^2
- C. 27π cm^2
- D. 36π cm^2
Correct Answer: C
Rationale: Rationale:
- The formula for the area of a circle is A = πr^2, where r is the radius of the circle.
- The diameter of the circular bandage is 6 cm, so the radius (r) is half of the diameter, which is 6/2 = 3 cm.
- Substitute the radius (r = 3 cm) into the formula for the area of a circle: A = π(3)^2 = 9π cm^2.
- Therefore, the area covered by the bandage is 9π cm^2.