A child's toy block is a cube with side lengths of 5cm. What is its total surface area?
- A. 25 sq cm
- B. 50 sq cm
- C. 125 sq cm
- D. 150 sq cm
Correct Answer: D
Rationale: The surface area of a cube is calculated using the formula: 6 * (side length)^2. Substituting the side length of 5cm into the formula, we get: 6 * (5cm)^2 = 6 * 25cm^2 = 150 sq cm. Therefore, the total surface area of the toy block is 150 sq cm. Choices A (25 sq cm), B (50 sq cm), and C (125 sq cm) are incorrect as they do not correctly calculate the total surface area of the cube.
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Bai Lin estimates that of her monthly paycheck, she puts 10% in savings and spends 30% on living expenses. If she has $1,545 left after that, how much is her monthly paycheck?
- A. $2,175
- B. $2,250
- C. $2,575
- D. $2,650
Correct Answer: C
Rationale: Let X be Bai Lin's monthly paycheck. From the given information, she puts 10% of X in savings and spends 30% on living expenses. This means she retains 60% (100% - 10% - 30%) of her paycheck, which equals $1,545. Therefore, 60% of X is $1,545. To find X, we divide $1,545 by 60% (or 0.60), which gives us X = $2,575. Hence, Bai Lin's monthly paycheck is $2,575. Therefore, the correct answer is $2,575. Choices A, B, and D are incorrect because they do not match the calculated monthly paycheck based on the given percentages and remaining amount.
A cake recipe calls for 2½ cups of flour. How many cups are needed to make 6 cakes?
- A. 12.5 cups
- B. 13 cups
- C. 14 cups
- D. 15 cups
Correct Answer: D
Rationale: To make one cake, you need 2½ cups of flour. To make 6 cakes, you would need 6 times the amount of flour for one cake, which is 2½ x 6 = 15 cups. Therefore, the correct answer is 15 cups. Choices A, B, and C are incorrect as they do not correctly calculate the total amount of flour needed for 6 cakes.
Relatively prime numbers share no common factors other than 1. Which of the following pairs of numbers are relatively prime?
- A. 12 and 16
- B. 15 and 17
- C. 20 and 24
- D. 28 and 36
Correct Answer: B
Rationale: Rationale:
- Relatively prime numbers are numbers that share no common factors other than 1.
- To determine if two numbers are relatively prime, we need to find the greatest common divisor (GCD) of the two numbers. If the GCD is 1, then the numbers are relatively prime.
- Let's calculate the GCD for each pair of numbers:
A) GCD(12, 16) = 4, not relatively prime
B) GCD(15, 17) = 1, relatively prime
C) GCD(20, 24) = 4, not relatively prime
D) GCD(28, 36) = 4, not relatively prime
Therefore, the pair of numbers 15 and 17 are relatively prime because their greatest common divisor is 1, meaning they share no common factors other than 1.
A patient weighs 180 pounds. What is their weight in kilograms (1kg = 2.2lbs)?
- A. 68kg
- B. 75kg
- C. 82kg
- D. 90kg
Correct Answer: C
Rationale: To convert pounds to kilograms, you need to divide the weight in pounds by the conversion factor of 2.2 (1kg = 2.2lbs).
180 pounds / 2.2 = 81.82 kg
Rounded to the nearest whole number, the weight of 180 pounds is approximately 82kg. Therefore, the correct answer is 82kg, which is option C. Option B (75kg) is not correct as it is significantly lower than the calculated value. Options A (68kg) and D (90kg) are also incorrect as they do not match the converted weight of 180 pounds.
A plan for a shed is drawn on a 1:10 scale. If the roof of the real shed measures 4 feet by 5 feet, what were the measurements on the plan?
- A. 80 inches by 100 inches
- B. 40 inches by 50 inches
- C. 4.8 inches by 6 inches
- D. 4 inches by 5 inches
Correct Answer: B
Rationale: When the real shed roof measures 4 feet by 5 feet, on a 1:10 scale plan, the measurements on the plan would be 1/10 of the real measurements. Therefore, the correct answer is 40 inches by 50 inches since it represents 1/10 of 4 feet by 5 feet. Choice A (80 inches by 100 inches) is incorrect because it is equivalent to the real shed measurements, not the scaled plan. Choice C (4.8 inches by 6 inches) is incorrect as it does not reflect the 1:10 scale reduction. Choice D (4 inches by 5 inches) is incorrect because it does not consider the scale factor of 1:10.
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