Solve for x: 4x + 2 = 18.
- A. x = 4
- B. x = 4
- C. x = 5
- D. x = 3
Correct Answer: B
Rationale: To solve for x, first, subtract 2 from both sides of the equation: 4x = 16. Then, divide by 4 to isolate x: x = 4. Choice A, x = 4, is the correct answer as calculated. Choice C, x = 5, is incorrect because the correct value of x is 4, not 5. Choice D, x = 3, is incorrect as well, as the correct value of x is 4, not 3.
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What is the probability of rolling an even number on a six-sided die?
- A. 50%
- B. 16.70%
- C. 25%
- D. 33.30%
Correct Answer: A
Rationale: The correct answer is A, 50%. A standard six-sided die has three even numbers (2, 4, 6) out of six possible outcomes. The probability of rolling an even number is therefore 3 out of 6, which simplifies to 50%. Choices B, C, and D are incorrect because they do not accurately reflect the probability of rolling an even number on a six-sided die.
You need to buy cardboard to cover a rectangular box with dimensions 40cm by 30cm by 25cm. Considering only the exterior surfaces (not flaps or openings), how much cardboard do you need (assume one sheet covers 0.5 sq m)?
- A. 0.3 sq m
- B. 0.6 sq m
- C. 1.2 sq m
- D. 1.8 sq m
Correct Answer: C
Rationale: To find the total surface area of the rectangular box, calculate the area of each side and sum them up. The areas of the sides are: 2(40x30) + 2(40x25) + 2(30x25) = 2400 + 2000 + 1500 = 5900 sq cm. Convert this to square meters by dividing by 10,000: 5900/10,000 = 0.59 sq m. Since one sheet covers 0.5 sq m, you would need 2 sheets to cover the box fully, which equals 1 sq m. Therefore, the correct answer is 1.2 sq m. Choice A (0.3 sq m) is too small for the dimensions provided. Choice B (0.6 sq m) is incorrect as it doesn't match the calculated surface area. Choice D (1.8 sq m) is too high for the surface area of the box.
If a runner runs 5 miles in 45 minutes, what is their average speed in miles per hour?
- A. 6.67 mph
- B. 5 mph
- C. 7 mph
- D. 10 mph
Correct Answer: A
Rationale: To find the average speed, first, convert 45 minutes to hours (45/60 = 0.75 hours). Then, divide the distance by the time: 5 miles · 0.75 hours = 6.67 mph. Choice A is correct because it accurately calculates the average speed based on the distance covered and time taken. Choice B is incorrect as it does not consider the time taken to cover the distance. Choice C is incorrect as it is higher than the calculated speed. Choice D is incorrect as it is higher and does not match the calculated average speed.
A nurse works in the military hospital from 1300 to 2000. How many hours does this nurse work?
- A. 8 hours
- B. 11 hours
- C. 7 hours
- D. 12 hours
Correct Answer: C
Rationale: The nurse works from 1300 to 2000, which is a 7-hour period. To calculate the hours worked, subtract the start time from the end time: 2000 - 1300 = 700, which is equal to 7 hours. Choice A, 8 hours, is incorrect as it does not reflect the actual duration. Choice B, 11 hours, is incorrect as it overestimates the hours worked. Choice D, 12 hours, is incorrect as it is also an overestimation of the hours worked.
Express 0.75 as a fraction.
- A. 4/5
- B. 3/4
- C. 1/2
- D. 1/4
Correct Answer: B
Rationale: To express 0.75 as a fraction, we write it as 75/100. Simplifying this fraction by dividing both the numerator and denominator by 25 gives us 3/4. Therefore, 0.75 is equivalent to 3/4. Choice A (4/5), Choice C (1/2), and Choice D (1/4) are incorrect fractions and do not represent 0.75.