What is 50% of 120?
- A. 50
- B. 50
- C. 70
- D. 60
Correct Answer: D
Rationale: The correct answer is D, 60. To find 50% of 120, you multiply 0.5 by 120: 0.5 x 120 = 60. Choice A and B are incorrect as they are duplicates. Choice C, 70, is incorrect because it is not the result of calculating 50% of 120.
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Subtract 15 3/4 - 8 2/5.
- A. 7 7/20
- B. 6 7/20
- C. 9 1/5
- D. 8 2/5
Correct Answer: A
Rationale: To subtract mixed numbers, find a common denominator. In this case, the common denominator is 20. Convert 15 3/4 to 15 15/20. Then, subtract 15 15/20 - 8 8/20 = 7 7/20. Therefore, the correct answer is A. Choice B is incorrect as it does not match the result of the subtraction. Choice C is incorrect as it is not the result of the subtraction. Choice D is incorrect as it represents the second number being subtracted, not the result of the subtraction.
What is 75% of 80?
- A. 35
- B. 45
- C. 70
- D. 60
Correct Answer: D
Rationale: To calculate 75% of 80, you multiply 0.75 by 80, which equals 60. Therefore, the correct answer is 60. Choices A, B, and C are incorrect because they do not represent 75% of 80. Choice A (35) is close to 50% of 80, Choice B (45) is close to 56.25% of 80, and Choice C (70) exceeds 80.
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.
What is the result of adding 1/4 + 3/8?
- A. 5/8
- B. 7/12
- C. 2/3
- D. 1/2
Correct Answer: A
Rationale: To add fractions with different denominators, find a common denominator. In this case, the common denominator of 4 and 8 is 8. Convert 1/4 to 2/8, then add it to 3/8. The sum is 5/8. Choice B (7/12) is incorrect as it is the result of adding 1/3 + 1/4. Choice C (2/3) is incorrect as it is the result of adding 3/8 + 1/4. Choice D (1/2) is incorrect as it is the result of adding 1/4 + 1/4.
A syringe holds 3ml of liquid. How many syringes are needed to measure 15ml of liquid?
- A. 3
- B. 5
- C. 7
- D. 9
Correct Answer: B
Rationale: Since each syringe holds 3ml of liquid, to measure 15ml of liquid, you would need to divide 15ml by 3ml/syringe. This calculation gives you 5 syringes needed to measure 15ml of liquid. Choice A (3 syringes) is incorrect because 3 syringes would only hold 9ml of liquid, not 15ml. Choice C (7 syringes) and Choice D (9 syringes) are incorrect as they would result in an excess amount of liquid, which is not needed.