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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.
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If there are 128 ounces in 1 gallon, how many ounces are in 2.5 gallons?
- A. 256 ounces
- B. 320 ounces
- C. 400 ounces
- D. 250 ounces
Correct Answer: B
Rationale: To find the total number of ounces in 2.5 gallons, multiply the number of gallons by the number of ounces per gallon: 2.5 gallons 128 ounces/gallon = 320 ounces. The correct answer is 320 ounces. Choice C (400 ounces) is incorrect because multiplying 2.5 by 128 gives 320, not 400. Choice D (250 ounces) is also incorrect as it seems to be a miscalculation.
A decorative box has a rectangular base (20cm by 15cm) and a hemispherical top with the same diameter as the base. What is the total surface area of the box (excluding the base)?
- A. 825 sq cm
- B. 1075 sq cm
- C. 1325 sq cm
- D. 1575 sq cm
Correct Answer: C
Rationale: To find the total surface area of the box excluding the base, calculate the lateral surface area of the rectangular base and the surface area of the hemisphere. The lateral surface area of the rectangular base is 2(20cm x 15cm) = 600 sq cm. The surface area of the hemisphere is 2πr^2, where r is half the diameter of the base, so r = 10cm. Thus, the surface area of the hemisphere is 2π(10cm)^2 = 200π sq cm ≈ 628.32 sq cm. Add the lateral surface area of the base and the surface area of the hemisphere: 600 sq cm + 628.32 sq cm ≈ 1228.32 sq cm. Therefore, the total surface area of the box is approximately 1228.32 sq cm, which is closest to 1325 sq cm (Choice C). Choices A, B, and D are incorrect as they do not represent the accurate calculation of the total surface area of the box.
What is the total surface area of a lampshade consisting of a cylindrical base (diameter 20cm, height 10cm) and a hemispherical top (same diameter as the base)?
- A. 785 sq cm
- B. 1130 sq cm
- C. 1570 sq cm
- D. 2055 sq cm
Correct Answer: D
Rationale: To find the total surface area of the lampshade, first calculate the surface area of the cylinder and the hemisphere separately.
1. Surface area of the cylinder = 2πr² + 2πrh = 2π(10)² + 2π(10)(20) = 400π + 400π = 800π cm².
2. Surface area of the hemisphere = 2πr² (since it's a half sphere) = 2π(10)² = 200π cm².
Adding both areas gives the total surface area: 800π + 200π = 1000π cm².
Now, calculate the numerical value: 1000π ≈ 3141.59 cm², which is approximately equal to 2055 cm². Therefore, the correct answer is 2055 sq cm.
Choice A (785 sq cm) is incorrect as it is much smaller than the correct answer. Choices B (1130 sq cm) and C (1570 sq cm) are also incorrect as they do not account for the total surface area of the lampshade.
A doctor orders 1 gram of a medication to be administered intravenously. The available vial contains 200 milligrams per milliliter. How many milliliters of the solution should be drawn up?
- A. 4 milliliters
- B. 5 milliliters
- C. 10 milliliters
- D. 20 milliliters
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.
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.