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A circle has an area of 121π in². Which of the following is the circumference of the circle in terms of pi (π)?
- A. 11π in
- B. 22π in
- C. 44π in
- D. 5.5π in
Correct Answer: B
Rationale: To find the circumference of the circle, we first need to determine the radius. Given that the area of the circle is 121π in², we use the formula for the area of a circle (A = πr²) to find the radius squared. So, r² = 121, which means the radius (r) is 11 in. The circumference of a circle is calculated using the formula 2πr. Substituting the radius value of 11 in, we get 2π(11) = 22π in. Therefore, the correct answer is 22π in. Choice A (11π in), Choice C (44π in), and Choice D (5.5π in) are incorrect because they do not correctly calculate the circumference based on the given area of the circle.
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What defines rational and irrational numbers?
- A. Any number that can be expressed as a fraction; any number that cannot be expressed as a fraction
- B. Any number that terminates or repeats; any number that does not terminate or repeat
- C. Any whole number; any decimal
- D. Any terminating decimal; any repeating decimal
Correct Answer: A
Rationale: Rational numbers are those that can be written as a simple fraction, including whole numbers and decimals that either terminate or repeat. Irrational numbers, on the other hand, cannot be expressed as fractions. Choice B is incorrect because not all rational numbers necessarily terminate or repeat. Choice C is incorrect as it oversimplifies the concept of rational and irrational numbers by only considering whole numbers and decimals. Choice D is incorrect as it inaccurately defines rational and irrational numbers solely based on decimals terminating or repeating, excluding the broader category of fractions.
A soccer field is rectangular in shape and is 100 meters long and 75 meters wide. The hectare is a metric unit of area often used to measure larger areas. Given that 1 hectare = 10,000 square meters, which of the following represents the soccer field's area in hectares?
- A. 0.75 hectares
- B. 7.5 hectares
- C. 7,500 hectares
- D. 75,000,000 hectares
Correct Answer: A
Rationale: To find the area of the soccer field, multiply its length by its width: 100 meters 75 meters = 7500 square meters. To convert this to hectares, divide by 10,000 (since 1 hectare = 10,000 square meters), resulting in 0.75 hectares. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not correctly convert the area to hectares. B and C are off by a factor of 10, while D is off by a factor of 10,000.
Two friends get frozen yogurt. The ratio of yogurt to toppings is 4:3. If one of the friends has 4.5 oz of toppings in their bowl, what is the amount of yogurt in their dessert?
- A. 6 oz
- B. 5.5 oz
- C. 3 oz
- D. 3.5 oz
Correct Answer: A
Rationale: The ratio 4:3 implies that for every 4 oz of yogurt, there are 3 oz of toppings. To find the amount of yogurt when the friend has 4.5 oz of toppings, we use the proportion: (4/3) 4.5 = 6 oz. Therefore, the amount of yogurt in their dessert is 6 oz. Choices B, C, and D are incorrect as they do not reflect the correct calculation based on the given ratio.
Which of the following is the most likely weight of a pencil?
- A. 25 kg
- B. 25 cm
- C. 25 mg
- D. 25 g
Correct Answer: D
Rationale: The correct answer is 25 g. Pencils are usually lightweight, and their weight is measured in grams. 25 kg (choice A) is too heavy for a pencil. 25 cm (choice B) is a unit of length, not weight. 25 mg (choice C) is too light for a pencil, as pencils typically weigh more than milligrams.
A homeowner has hired two people to mow his lawn. If person A is able to mow the lawn in 2 hours by herself and person B is able to mow the lawn in 3 hours by himself, what is the amount of time it would take for both person A and B to mow the lawn together?
- A. 5 hours
- B. 2.5 hours
- C. 1.2 hours
- D. 1 hour
Correct Answer: C
Rationale: To find the combined work rate, you add the individual work rates: 1/2 + 1/3 = 5/6. This means that together, they can mow 5/6 of the lawn per hour. To determine how long it would take for both A and B to mow the entire lawn, you take the reciprocal of 5/6, which gives you 6/5 or 1.2 hours. Therefore, it would take 1.2 hours for person A and person B to mow the lawn together. Choice A (5 hours) is incorrect because it does not consider the combined efficiency of both workers. Choice B (2.5 hours) is incorrect as it does not reflect the correct calculation based on the combined work rates of the two individuals. Choice D (1 hour) is incorrect as it doesn't consider the fact that the combined rate is less than the individual rate of person A alone, thus taking longer than 1 hour.