Nokea
Solve for y if y = 3: 4y + 21 / y.
- A. 7.7
- B. 19
- C. 23/3
- D. 11
Correct Answer: B
Rationale: To solve for y, substitute y = 3 into the equation: 4(3) + 21 / 3 = 12 + 7 = 19. Therefore, the correct answer is 19. Choice A (7.7) is incorrect as it does not result from the substitution. Choice C (23/3) is incorrect as it does not match the calculated value. Choice D (11) is incorrect, as it is not the result of the provided equation.
You may also like to solve these questions
What is 60% of 150?
- A. 80
- B. 90
- C. 120
- D. 80
Correct Answer: B
Rationale: To find 60% of 150, you multiply 0.6 by 150, which equals 90. Therefore, the correct answer is 90. Choice A (80) is incorrect because it does not represent 60% of 150. Choice C (120) is incorrect as it exceeds 100% of 150. Choice D (80) is a duplicate of choice A and does not accurately represent 60% of 150.
Multiply: 4/9 1 4/5 2/5.
- A. 8/25
- B. 1 & 10/19
- C. 7/16
- D. 32/45
Correct Answer: A
Rationale: To multiply the fractions, convert the mixed numbers to improper fractions: 1 4/5 = 9/5. Then, multiply the fractions: (4/9) (9/5) (2/5) = 8/25. The correct answer is A. Choice B is incorrect as it does not match the result of the multiplication. Choice C is incorrect as it is not the result of multiplying the fractions. Choice D is incorrect as it is not the result of the given multiplication.
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.
If the quotient is 4 and the dividend is 12, what is the divisor?
- A. 3
- B. 6
- C. 4
- D. 9
Correct Answer: C
Rationale: To find the divisor, you need to divide the dividend by the quotient. In this case, the dividend is 12 and the quotient is 4. Dividing 12 by 4 gives you the divisor, which is 3. Therefore, the correct answer is 4. Choices A, B, and D are incorrect because they do not result from dividing the dividend by the quotient in this scenario.
What is the probability of rolling a 3 on a six-sided die?
- A. 1/6
- B. 1/4
- C. 1/3
- D. 1/2
Correct Answer: A
Rationale: The probability of rolling a specific number on a six-sided die is calculated by dividing the favorable outcomes (rolling a 3) by the total possible outcomes. In this case, there is 1 favorable outcome (rolling a 3) out of 6 total possible outcomes (numbers 1 to 6 on the die). Therefore, the probability of rolling a 3 is 1/6. Choice B (1/4), C (1/3), and D (1/2) are incorrect because they do not represent the correct calculation of the probability for rolling a 3 on a six-sided die.