Nokea
What is the volume of water needed to fill a rectangular swimming pool with dimensions 10 meters by 5 meters and a depth of 2 meters?
- A. 50 cu m
- B. 100 cu m
- C. 150 cu m
- D. 200 cu m
Correct Answer: B
Rationale: To find the volume of the rectangular swimming pool, you need to multiply the length by the width by the depth. Volume = Length x Width x Depth. Therefore, Volume = 10m x 5m x 2m = 100 cubic meters. This means it takes 100 cubic meters of water to fill the pool. Choices A, C, and D are incorrect as they do not correctly calculate the volume based on the provided dimensions.
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Solve for x: 2 : 5 :: 64 : x
- A. 32
- B. 70
- C. 128
- D. 160
Correct Answer: C
Rationale: The symbol '::' represents a proportion in which the first pair of numbers is related to the second pair of numbers. To solve for x in the proportion 2 : 5 :: 64 : x, you can set up a proportion equation: 2/5 = 64/x. Cross-multiplying gives you 2x = 5 * 64, which simplifies to 2x = 320. Dividing both sides by 2, you get x = 160. Therefore, x = 128 is the correct answer. Choice A (32) is incorrect as it is not the result of solving the proportion equation. Choice B (70) is incorrect as it is not related to the given proportion. Choice D (160) is a common mistake made by wrongly interpreting the equation; the correct value of x is 128.
What is the absolute value of -7?
- A. 49
- B. 17
- C. 7
- D. 14
Correct Answer: C
Rationale: The absolute value of a number is its distance from zero on the number line, regardless of its sign. In this case, the absolute value of -7 is 7 because it is 7 units away from zero in the negative direction. Therefore, the absolute value of -7 is 7. Choice A (49) is incorrect as it is the square of -7, not the absolute value. Choice B (17) and Choice D (14) are incorrect values and do not represent the absolute value of -7.
A scientific illustrator uses a scale of 3:1 for drawings of insects. If the length of a cicada in the drawing is 6 centimeters, how long is the actual cicada in real life?
- A. 18 centimeters
- B. 6.3 centimeters
- C. 4.6 centimeters
- D. 4.2 centimeters
Correct Answer: A
Rationale: The scale of 3:1 means that for every 3 centimeters in the drawing, it represents 1 centimeter in real life. If the length of the cicada in the drawing is 6 centimeters, in real life, it would be 6 x 3 = 18 centimeters long. Therefore, the actual length of the cicada in real life is 18 centimeters. Choice B, 6.3 centimeters, is incorrect because it does not account for the scale factor. Choices C and D, 4.6 centimeters and 4.2 centimeters respectively, are also incorrect as they do not consider the 3:1 scale used in the drawing.
Multiply: 54 45. Express the result in decimal form.
- A. 0.0243
- B. 0.243
- C. 2.43
- D. 24.3
Correct Answer: D
Rationale: To multiply 54 by 45, you should multiply the two numbers together: 54 x 45 = 2430. The decimal point is placed after counting the total decimal places in the numbers being multiplied. As there are no decimal places in the numbers 54 and 45, the result is 2430, which is correctly expressed as 24.3 when considering the decimal point placement. Choice A (0.0243) and Choice B (0.243) are incorrect as they represent fractions of 2430. Choice C (2.43) is incorrect as it incorrectly places the decimal point one place before the actual result.
If the total cost of his purchase was $9.38 and he gave the cashier $20, how much change did he receive?
- A. $0.62
- B. $5.02
- C. $9.38
- D. $10.62
Correct Answer: D
Rationale: To determine the amount of change received, you need to subtract the total cost from the amount given. $20 - $9.38 = $10.62. Therefore, he received $10.62 in change. Option A ($0.62) is incorrect as it is the difference in cents, not dollars. Option B ($5.02) is incorrect as it does not reflect the correct subtraction. Option C ($9.38) is incorrect as it represents the total cost of the purchase, not the change received.