What percentage of her income is left after Mary spent 15%?
- A. 12%
- B. 85%
- C. 75%
- D. 95%
Correct Answer: B
Rationale: To determine the percentage of income remaining after spending 15%, subtract the percentage spent from 100% (100% - 15% = 85%). Therefore, Mary has 85% of her income left, which aligns with answer choice B. Choice A (12%) is incorrect because it represents the remaining amount after spending 88% of her income. Choice C (75%) is incorrect as it does not account for the 15% already spent. Choice D (95%) is incorrect as it does not consider the amount spent by Mary.
You may also like to solve these questions
A rancher has a herd of different-colored horses in his corral. Ten of the horses are black, six are brown, eight are two-color horses, and three are all white. What percentage of the horses are brown? (Round to the nearest whole number if necessary).
- A. 15%
- B. 20%
- C. 25%
- D. 30%
Correct Answer: B
Rationale: To find the percentage of brown horses, first calculate the total number of horses: 10 black + 6 brown + 8 two-color + 3 all white = 27 horses. Then, calculate the percentage of brown horses: (6 · 27) 100 = 22.22%, which rounds to 20%. Choice B, 20%, is the correct answer. Choice A, 15%, is incorrect as it does not reflect the accurate percentage of brown horses. Choice C, 25%, is incorrect as it overestimates the percentage of brown horses. Choice D, 30%, is incorrect as it also overestimates the percentage of brown horses.
How many meters are in 5 kilometers?
- A. 1000
- B. 5000
- C. 10000
- D. 500
Correct Answer: B
Rationale: To convert kilometers to meters, you need to multiply the number of kilometers by 1000 since there are 1000 meters in 1 kilometer. Therefore, 5 kilometers is equal to 5 1000 = 5000 meters. Choice A (1000) is incorrect because it represents the number of meters in 1 kilometer, not 5 kilometers. Choice C (10000) is incorrect as it is the result of multiplying 10 (not 5) by 1000. Choice D (500) is incorrect as it represents half the correct conversion value.
If a rat can finish a maze in about 3 minutes, how much longer will it take the rat to finish the maze if a small backpack is put on it, reducing its speed by 50%?
- A. 3 minutes
- B. 4 minutes
- C. 6 minutes
- D. 1.5 minutes
Correct Answer: C
Rationale: Reducing the rat's speed by 50% means it will take twice as long to finish the maze. Since the original time is 3 minutes, doubling that gives 6 minutes. Therefore, the total time will be 6 minutes, making the correct answer C. Choice A (3 minutes) is the original time it takes the rat to finish the maze, not the time with the backpack. Choice B (4 minutes) is not correct as reducing the speed by 50% would double the original time. Choice D (1.5 minutes) is incorrect as halving the time is not the effect of reducing the speed by 50%.
How many meters are in 3 kilometers?
- A. 3000 meters
- B. 2000 meters
- C. 3500 meters
- D. 2500 meters
Correct Answer: A
Rationale: The correct answer is A: 3000 meters. To convert kilometers to meters, you need to know that there are 1000 meters in 1 kilometer. Therefore, to find the number of meters in 3 kilometers, you multiply 3 by 1000, resulting in 3000 meters. Choice B, 2000 meters, is incorrect as it doesn't account for the correct conversion factor. Choice C, 3500 meters, and Choice D, 2500 meters, are also incorrect as they provide inaccurate conversions.
Percent Increase/Decrease: A medication dosage is increased by 20%. If the original dosage was 100mg, what is the new dosage?
- A. 80mg
- B. 100mg
- C. 120mg
- D. 140mg
Correct Answer: C
Rationale: Calculate the increase in dosage: 100mg * 20% = 100mg * 0.20 = 20mg. Add the increase to the original dosage to find the new dosage: 100mg + 20mg = 120mg. Therefore, the new dosage is 120mg after a 20% increase from the original 100mg dosage. Choice A (80mg) is incorrect because it represents a decrease rather than an increase. Choice B (100mg) is the original dosage and does not account for the 20% increase. Choice D (140mg) is incorrect as it is the original dosage plus 40%, not the 20% increase specified.