Nokea
Solve the system of equations.
Equation 1: 2x + y = 0
Equation 2: x - 2y = 8
- A. (1.8, 3.6) and (-1.8, -3.6)
- B. (1.8, -3.6) and (-1.8, 3.6)
- C. (1.3, 2.6) and (-1.3, -2.6)
- D. (-1.3, 2.6) and (1.3, -2.6)
Correct Answer: B
Rationale: From Equation 1: 2x + y = 0. Solve for y: y = -2x. Substitute y = -2x into Equation 2: x - 2(-2x) = 8. Simplify to x + 4x = 8, then 5x = 8, and x = 8 · 5 = 1.6. Substitute x = 1.6 back into y = -2x to find y = -3.2. Therefore, one solution is (1.6, -3.2). To find the second solution, use -1.6 for x to get (-1.6, 3.2). Thus, the correct answer is B, representing the solutions (1.8, -3.6) and (-1.8, 3.6). Choices A, C, and D contain incorrect values that do not match the solutions derived from solving the system of equations.
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What is the result of multiplying (3/5) by (5/8)?
- A. 3/8
- B. 3/5
- C. 15/40
- D. 3/30
Correct Answer: A
Rationale: To multiply fractions, multiply the numerators together and the denominators together. For (3/5) * (5/8), you get (3*5) / (5*8) = 15 / 40, which simplifies to 3/8. Therefore, the correct answer is A. Choice B (3/5) is incorrect as it is one of the original fractions being multiplied. Choice C (15/40) is the result of the multiplication but not simplified to its lowest terms. Choice D (3/30) is incorrect as the numerator is not the result of multiplying 3 and 5 together.
If a tree grows an average of 4.2 inches in a day, what is the rate of change in its height per month? Assume a month is 30 days.
- A. 0.14 inches per month
- B. 4.2 inches per month
- C. 34.2 inches per month
- D. 126 inches per month
Correct Answer: D
Rationale: The tree grows at an average rate of 4.2 inches per day. To find the rate of change per month, multiply the daily growth rate by the number of days in a month (30 days):
4.2 inches/day 30 days = 126 inches per month.
Therefore, the rate of change in the tree's height is 126 inches per month, making option D the correct answer. Option A is incorrect because it miscalculates the rate based on daily growth. Option B is incorrect as it doesn't account for the total days in a month. Option C is incorrect as it overestimates the monthly growth rate.
What is the mode of the data set: 2, 3, 3, 4, 4, 4, 5?
- A. 2
- B. 3
- C. 4
- D. 5
Correct Answer: C
Rationale: The mode of a data set is the value that appears most frequently. In this data set (2, 3, 3, 4, 4, 4, 5), the number 4 appears three times, which is more frequent than any other number in the set. Therefore, the correct answer is 4. Choice A (2), B (3), and D (5) do not appear as frequently as 4 in the data set, so they are not the mode.
Write 290% as a fraction.
- A. 29/10
- B. 58/20
- C. 145/50
- D. 290/100
Correct Answer: D
Rationale: To convert a percentage to a fraction, you write the percentage as the numerator of the fraction over 100. Therefore, 290% is equivalent to 290/100, which simplifies to 29/10. Choices A, B, and C are incorrect because they do not represent 290% as a fraction by placing the percentage value over 100.
Which statement about multiplication and division is true?
- A. The product of the quotient and the dividend is the divisor.
- B. The product of the dividend and the divisor is the quotient.
- C. The product of the quotient and the divisor is the dividend.
- D. None of the above.
Correct Answer: C
Rationale: In division, the dividend is the number being divided, the divisor is the number you are dividing by, and the quotient is the result. Multiplying the quotient by the divisor gives the original dividend. This is the reverse of the division operation. Therefore, the correct statement is that the product of the quotient and the divisor equals the dividend, making option C correct. Choices A and B provide incorrect relationships between the terms dividend, divisor, quotient, and product, making them inaccurate. Option D is a general statement that does not provide the correct relationship between multiplication and division terms.