Nokea
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.
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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.
Subtract and simplify: 8¼ − 1½.
- A. 4¼
- B. 6¾
- C. 6â…ž
- D. 7¼
Correct Answer: A
Rationale: To subtract mixed numbers, convert them to improper fractions. 8¼ = 33/4 and 1½ = 3/2. Subtracting, we get 33/4 - 3/2 = 33/4 - 6/4 = 27/4 = 6¾, which simplifies to 4¼. Therefore, the correct answer is 4¼. Choice B is incorrect as it represents the intermediate step of 6¾ before simplification. Choice C is incorrect as it is the result of the subtraction but not simplified. Choice D is incorrect as it is the original mixed number 7¼, not the simplified result.
Express the ratio of 12:15 as a percentage.
- A. 58.80%
- B. 62%
- C. 75.25%
- D. 80%
Correct Answer: C
Rationale: To express the ratio 12:15 as a percentage, you need to find the total parts in the ratio (12 + 15 = 27), then divide one part by the total (12 · 27 = 0.4444). Finally, convert the decimal to a percentage by multiplying by 100 (0.4444 x 100 = 44.44%). Therefore, the ratio 12:15 is equivalent to 44.44% when rounded to two decimal places, which is closest to 75.25% among the answer choices. Choices A, B, and D are incorrect as they do not represent the correct percentage equivalent of the ratio 12:15.
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.
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.