Nokea
Solve the equation for the unknown. 3x + 2 = 20
- A. x = 2
- B. x = 4
- C. x = 6
- D. x = 8
Correct Answer: C
Rationale: Simplify the equation step by step:
Subtract 2 from both sides:
3x + 2 - 2 = 20 - 2
3x = 18
Divide both sides by 3:
x = 18 · 3
x = 6
Therefore, the correct answer is C (x = 6).
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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.
A cell has a diameter of 0.1 meter, and another cell has a diameter of 0.05 meters. How many times larger is the first cell compared to the second cell?
- A. 2
- B. 4
- C. 8
- D. 16
Correct Answer: A
Rationale: To determine how many times larger the first cell is compared to the second cell, divide the diameter of the first cell by the diameter of the second cell: 0.1 / 0.05 = 2. Therefore, the first cell is 2 times larger than the second cell. Choice B, C, and D are incorrect because they do not provide the accurate calculation for the size difference between the two cells.
A piece of wood that is 7 1/2 feet long has 3 1/4 feet cut off. How many feet of wood remain?
- A. 4 1/4 feet
- B. 4 1/2 feet
- C. 3 1/2 feet
- D. 3 3/4 feet
Correct Answer: A
Rationale: To find the remaining length of wood, you need to subtract 3 1/4 feet from 7 1/2 feet. When you subtract the fractions, 7 1/2 - 3 1/4, you get 15/2 - 13/4 = 30/4 - 13/4 = 17/4 = 4 1/4 feet. Therefore, the correct answer is 4 1/4 feet. Choice B (4 1/2 feet) is incorrect because the subtraction result is not 1/2. Choice C (3 1/2 feet) is incorrect as it does not match the correct result of 4 1/4 feet. Choice D (3 3/4 feet) is also incorrect as it does not align with the correct answer obtained from the subtraction of fractions.
Eric buys 5 1/2 pounds of apples each week for four weeks. How many total pounds does he buy?
- A. 22 pounds
- B. 20 pounds
- C. 18 pounds
- D. 24 pounds
Correct Answer: A
Rationale: To find the total pounds of apples Eric buys, you need to multiply the pounds of apples bought each week (5 1/2 pounds) by the number of weeks (4 weeks). When you multiply 5 1/2 by 4, you get 22 pounds. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not accurately calculate the total pounds purchased over the four weeks.
Jayden rides his bike for 5/8 miles. He takes a break and rides another 3/4 miles. How many miles does he ride?
- A. 1 3/8 miles
- B. 1 1/2 miles
- C. 1 7/8 miles
- D. 2 miles
Correct Answer: A
Rationale: To find the total distance Jayden rides, you need to add the fractions 5/8 + 3/4. To add these fractions, you must ensure they have a common denominator. In this case, the common denominator is 8. So, 5/8 + 3/4 = 5/8 + 6/8 = 11/8. Since 11/8 can be simplified to 1 3/8, Jayden rides a total of 1 3/8 miles. Choice B (1 1/2 miles), Choice C (1 7/8 miles), and Choice D (2 miles) are incorrect as they do not accurately represent the total distance calculated by adding the two fractions, which is 1 3/8 miles.