John worked at a bookstore for two weeks. The second week he earned 20 percent more than he did the first week. If he earned $300 the second week, how much did he earn the first week?
- A. 240
- B. 250
- C. 280
- D. 380
Correct Answer & Rationale
Correct Answer: B
To determine John’s earnings for the first week, we know that his second week earnings were 20% more than the first week. If he earned $300 in the second week, we can calculate his first week earnings by setting up the equation: Let x be the first week’s earnings. Then, x + 0.2x = 300. This simplifies to 1.2x = 300. Dividing both sides by 1.2 gives x = 250. Option A ($240) is too low, as it would not result in a $300 second week. Option C ($280) would imply a second week earning of $336, which exceeds $300. Option D ($380) is also incorrect as it suggests a second week earning of $456. Thus, $250 is the only viable answer.
To determine John’s earnings for the first week, we know that his second week earnings were 20% more than the first week. If he earned $300 in the second week, we can calculate his first week earnings by setting up the equation: Let x be the first week’s earnings. Then, x + 0.2x = 300. This simplifies to 1.2x = 300. Dividing both sides by 1.2 gives x = 250. Option A ($240) is too low, as it would not result in a $300 second week. Option C ($280) would imply a second week earning of $336, which exceeds $300. Option D ($380) is also incorrect as it suggests a second week earning of $456. Thus, $250 is the only viable answer.
Other Related Questions
The large square above has area 1 and is divided into 25 squares of equal area. Which of the following represents the area of the shaded region?
- A. 0.8
- B. 0.16
- C. 0.24
- D. 0.32
Correct Answer & Rationale
Correct Answer: D
In a large square with an area of 1, each of the 25 smaller squares has an area of \( \frac{1}{25} = 0.04 \). To find the area of the shaded region, count the number of shaded squares. If there are 8 shaded squares, then the area of the shaded region is \( 8 \times 0.04 = 0.32 \). Option A (0.8) is incorrect as it exceeds the total area of the large square. Option B (0.16) represents 4 shaded squares, which is not consistent with the given information. Option C (0.24) suggests 6 shaded squares, which also does not match. Thus, the area of the shaded region is accurately represented by option D, 0.32.
In a large square with an area of 1, each of the 25 smaller squares has an area of \( \frac{1}{25} = 0.04 \). To find the area of the shaded region, count the number of shaded squares. If there are 8 shaded squares, then the area of the shaded region is \( 8 \times 0.04 = 0.32 \). Option A (0.8) is incorrect as it exceeds the total area of the large square. Option B (0.16) represents 4 shaded squares, which is not consistent with the given information. Option C (0.24) suggests 6 shaded squares, which also does not match. Thus, the area of the shaded region is accurately represented by option D, 0.32.
3/8 expressed as a percent is
- A. 3.75%
- B. 37.50%
- C. 38%
- D. 38,1/3%
Correct Answer & Rationale
Correct Answer: B
To convert a fraction to a percent, multiply by 100. For 3/8, the calculation is (3 ÷ 8) × 100, which equals 37.5%. This aligns with option B: 37.50%. Option A (3.75%) results from miscalculating the fraction, likely confusing the decimal representation. Option C (38%) rounds up incorrectly, as it does not accurately reflect the precise conversion. Option D (38, 1/3%) misrepresents the fraction by suggesting a value that exceeds the actual percentage, further indicating a misunderstanding of the conversion process. Thus, option B is the only accurate representation of 3/8 as a percent.
To convert a fraction to a percent, multiply by 100. For 3/8, the calculation is (3 ÷ 8) × 100, which equals 37.5%. This aligns with option B: 37.50%. Option A (3.75%) results from miscalculating the fraction, likely confusing the decimal representation. Option C (38%) rounds up incorrectly, as it does not accurately reflect the precise conversion. Option D (38, 1/3%) misrepresents the fraction by suggesting a value that exceeds the actual percentage, further indicating a misunderstanding of the conversion process. Thus, option B is the only accurate representation of 3/8 as a percent.
Frederica used 13.4 gallons of gasoline to drive 448.9 miles. What was the average number of miles she drove per gallon of gasoline?
- A. 3.4 mpg
- B. 33.5 mpg
- C. 60.15 mpg
- D. 435.5 mpg
Correct Answer & Rationale
Correct Answer: B
To find the average miles per gallon (mpg), divide the total miles driven by the gallons used. Here, 448.9 miles divided by 13.4 gallons equals approximately 33.5 mpg. Option A (3.4 mpg) is incorrect as it significantly underestimates the fuel efficiency. Option C (60.15 mpg) overestimates the efficiency, suggesting an unrealistic performance for a typical vehicle. Option D (435.5 mpg) is also incorrect, as it implies an implausibly high efficiency that is not achievable with conventional vehicles. Thus, the calculation confirms that 33.5 mpg accurately represents Frederica's fuel efficiency.
To find the average miles per gallon (mpg), divide the total miles driven by the gallons used. Here, 448.9 miles divided by 13.4 gallons equals approximately 33.5 mpg. Option A (3.4 mpg) is incorrect as it significantly underestimates the fuel efficiency. Option C (60.15 mpg) overestimates the efficiency, suggesting an unrealistic performance for a typical vehicle. Option D (435.5 mpg) is also incorrect, as it implies an implausibly high efficiency that is not achievable with conventional vehicles. Thus, the calculation confirms that 33.5 mpg accurately represents Frederica's fuel efficiency.
7.50 ÷ 0.125 =
- A. 60
- B. 6
- C. 0.6
- D. 1/6
Correct Answer & Rationale
Correct Answer: A
To solve 7.50 ÷ 0.125, it's helpful to convert the division into a more manageable form. Dividing by 0.125 is the same as multiplying by 8 (since 1 ÷ 0.125 = 8). Therefore, 7.50 × 8 equals 60, confirming option A as the right choice. Option B (6) is incorrect; it underestimates the quotient significantly. Option C (0.6) is also wrong, as it suggests a much smaller result than what is obtained. Lastly, option D (1/6) misrepresents the division entirely, implying a fractional outcome that does not align with the calculations.
To solve 7.50 ÷ 0.125, it's helpful to convert the division into a more manageable form. Dividing by 0.125 is the same as multiplying by 8 (since 1 ÷ 0.125 = 8). Therefore, 7.50 × 8 equals 60, confirming option A as the right choice. Option B (6) is incorrect; it underestimates the quotient significantly. Option C (0.6) is also wrong, as it suggests a much smaller result than what is obtained. Lastly, option D (1/6) misrepresents the division entirely, implying a fractional outcome that does not align with the calculations.