Multiply 12 by 15 and express the result as a decimal:
- A. 0.0018
- B. 0.018
- C. 0.18
- D. 1.8
Correct Answer: D
Rationale: To find the product of 12 and 15, you simply multiply them together. 12 multiplied by 15 equals 180. To express 180 as a decimal, you divide by 100. Therefore, the correct answer is 1.8. Choices A, B, and C are incorrect as they represent values that are not the correct result of multiplying 12 by 15 and converting it to a decimal.
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After putting â…“ aside for her share of rent and utilities and spending $75 on groceries, what is left from her weekly paycheck?
- A. $150
- B. $214.86
- C. $204.26
- D. $192.76
Correct Answer: A
Rationale: If she puts aside 1/3 of her paycheck for rent and utilities, this means she spends 3 portions in total. So, 1 portion represents 1/3 of the paycheck. Since she spends $75 on groceries, it leaves 2 portions. The total amount of 3 portions is the paycheck. To find out one portion, divide the total paycheck by 3: Paycheck = 3 portions. $75 is one portion. Multiply the one portion by 3 to find the total paycheck: $75 * 3 = $225. Subtract the spent amount from the weekly paycheck: $225 - $75 = $150. Therefore, the amount left from her weekly paycheck is $150. The other choices are incorrect because they do not follow the correct calculation based on the given information.
Which of the following numbers is NOT divisible by 3?
- A. 105
- B. 141
- C. 273
- D. 810
Correct Answer: D
Rationale: To determine if a number is divisible by 3, we can check if the sum of its digits is divisible by 3. If the sum of the digits is divisible by 3, then the original number is also divisible by 3.
A) 105: 1 + 0 + 5 = 6, which is divisible by 3. Therefore, 105 is divisible by 3.
B) 141: 1 + 4 + 1 = 6, which is divisible by 3. Therefore, 141 is divisible by 3.
C) 273: 2 + 7 + 3 = 12, which is divisible by 3. Therefore, 273 is divisible by 3.
D) 810: 8 + 1 + 0 = 9, which is not divisible by 3. Therefore, 810 is NOT divisible by 3.
Therefore, the correct answer is D (810). Choices A, B, and C are all divisible by 3 as the sum of their digits is divisible by 3.
A solution is 60% alcohol. If 200ml of the solution is used, how much pure alcohol is present?
- A. 100ml
- B. 120ml
- C. 140ml
- D. 160ml
Correct Answer: B
Rationale: If the solution is 60% alcohol, it means that 60% of the solution is alcohol. Therefore, in 200ml of the solution, the amount of alcohol present is: 200ml * 60% = 200ml * 0.60 = 120ml. So, when 200ml of the solution is used, there are 120ml of pure alcohol present. Choice A, 100ml, is incorrect because it does not account for the correct percentage of alcohol in the solution. Choice C, 140ml, and Choice D, 160ml, are incorrect as they overestimate the amount of pure alcohol present in the solution.
Multiply: 6 0.06 =
- A. 0.0036
- B. 0.036
- C. 0.36
- D. 3.6
Correct Answer: C
Rationale: When multiplying 6 by 0.06, you can treat 0.06 as 6 hundredths. So, 6 0.06 is equivalent to 6 6 hundredths, which equals 0.36. The correct answer is 0.36. Choice A (0.0036) is incorrect because it represents 6 multiplied by 0.0006, not 0.06. Choice B (0.036) is incorrect as it represents 6 multiplied by 0.06 without considering the position of the decimal point. Choice D (3.6) is incorrect as it represents 6 multiplied by 6, not by 0.06.
A team from the highway department can replace 14 streetlights in 7 hours of work. If they work a 30-hour week at this job, in how many weeks will they replace all 120 downtown streetlights?
- A. 1½ weeks
- B. 2 weeks
- C. 2½ weeks
- D. 3 weeks
Correct Answer: B
Rationale: If the team can replace 14 streetlights in 7 hours, it means they replace 2 streetlights per hour. In a 30-hour week, they can therefore replace 2 x 30 = 60 streetlights. To replace all 120 downtown streetlights, they will need 120 / 2 = 60 hours, which is equivalent to 60 / 30 = 2 weeks. Therefore, the correct answer is 2 weeks. Choice A, 1½ weeks, is incorrect because it doesn't consider the total number of streetlights that need to be replaced. Choice C, 2½ weeks, is incorrect as it overestimates the time needed. Choice D, 3 weeks, is incorrect as it underestimates the efficiency of the team in replacing streetlights.
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