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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.
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Louise wins $25 in a raffle at the fair. She spends $50 on an apple pie and $25 on lemonade. How much of her winnings does she take home?
- A. $12.75
- B. $16.25
- C. $18.25
- D. $19.50
Correct Answer: B
Rationale: Louise's total spending is $50 + $25 = $75. To find out how much of her winnings she takes home, we need to subtract her total spending from her winnings: $25 - $75 = -$50. Louise actually loses $50 as she spends more than her winnings. Therefore, she doesn't take home any money and would be in debt by $50. The correct answer is $25 - $75 = -$50, indicating that she does not take home any winnings and is in a deficit.
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.
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.
Rectangle: A picture frame measures 15cm by 20cm. What is its perimeter?
- A. 30cm
- B. 55cm
- C. 65cm
- D. 75cm
Correct Answer: C
Rationale: To find the perimeter of a rectangle, you add the lengths of all sides. The formula for the perimeter of a rectangle is 2 * (length + width). In this case, the length is 15cm and the width is 20cm. Therefore, the perimeter = 2 * (15cm + 20cm) = 65cm. Choice A (30cm), Choice B (55cm), and Choice D (75cm) are incorrect as they do not correctly calculate the perimeter of the given rectangle.
A plan for a barn is drawn on a 1:30 scale. If the width of a barn door on the plan measures 3 inches, what is the actual width of the finished door?
- A. 90 inches
- B. 10 feet
- C. 9 feet
- D. 7.5 feet
Correct Answer: B
Rationale: The scale of 1:30 means that 1 inch on the plan represents 30 inches in actual size. If the width of the barn door on the plan is 3 inches, the actual width is calculated by multiplying 3 inches by the scale factor (30), giving 90 inches. To convert inches to feet, divide by 12 (since 12 inches = 1 foot), resulting in 90 inches · 12 = 7.5 feet. Therefore, the correct answer is 10 feet (option B), not 7.5 feet. Option A (90 inches) is the result before converting to feet, option C (9 feet) is the incorrect conversion if the initial calculation was done correctly, and option D (7.5 feet) is the incorrect conversion of the initial calculation.