Question
Match the following equation to the correct situation.
20%(b − 21) = 20%b − 4.2
A.
An amount of chili was eaten from 20% of 4.2 less than b bowls.
B.
A number of songs are available for download from 20% of b artists.
C.
A number of cups of coffee were thrown away by 20% of b senators during 4.2 speeches.
D.
Last month's electricity bill was 4.2 kW-h less than 20% of this month's bill.
20%(b − 21) = 20%b − 4.2
A.
An amount of chili was eaten from 20% of 4.2 less than b bowls.
B.
A number of songs are available for download from 20% of b artists.
C.
A number of cups of coffee were thrown away by 20% of b senators during 4.2 speeches.
D.
Last month's electricity bill was 4.2 kW-h less than 20% of this month's bill.
Answers
GPT-4o mini
To match the equation \(20\%(b - 21) = 20\%b - 4.2\) to the correct situation, we can analyze both sides of the equation:
1. **Left Side**: \(20\%(b - 21)\) implies taking 20% of \((b - 21)\), meaning a reduction from \(b\) by 21 before calculating 20%.
2. **Right Side**: \(20\%b - 4.2\) suggests taking 20% of \(b\) and then subtracting 4.2.
Now let's evaluate the situations:
A. **An amount of chili was eaten from 20% of 4.2 less than b bowls.**
- This implies a calculation involving \(b - 4.2\), not directly matching the equation.
B. **A number of songs are available for download from 20% of b artists.**
- This scenario does not align with the equation since it doesn't involve any subtraction relating to 21 or 4.2.
C. **A number of cups of coffee were thrown away by 20% of b senators during 4.2 speeches.**
- This also does not fit as there’s no reference to subtraction or adjustments involving 21 or 4.2 in terms of percentages.
D. **Last month's electricity bill was 4.2 kW-h less than 20% of this month's bill.**
- This situation aligns most closely, as it discusses taking 20% of the current bill (comparable to \(b\)) and noting a reduction by 4.2 (just like the right side of the equation).
Thus, the correct match is:
**D. Last month's electricity bill was 4.2 kW-h less than 20% of this month's bill.**
1. **Left Side**: \(20\%(b - 21)\) implies taking 20% of \((b - 21)\), meaning a reduction from \(b\) by 21 before calculating 20%.
2. **Right Side**: \(20\%b - 4.2\) suggests taking 20% of \(b\) and then subtracting 4.2.
Now let's evaluate the situations:
A. **An amount of chili was eaten from 20% of 4.2 less than b bowls.**
- This implies a calculation involving \(b - 4.2\), not directly matching the equation.
B. **A number of songs are available for download from 20% of b artists.**
- This scenario does not align with the equation since it doesn't involve any subtraction relating to 21 or 4.2.
C. **A number of cups of coffee were thrown away by 20% of b senators during 4.2 speeches.**
- This also does not fit as there’s no reference to subtraction or adjustments involving 21 or 4.2 in terms of percentages.
D. **Last month's electricity bill was 4.2 kW-h less than 20% of this month's bill.**
- This situation aligns most closely, as it discusses taking 20% of the current bill (comparable to \(b\)) and noting a reduction by 4.2 (just like the right side of the equation).
Thus, the correct match is:
**D. Last month's electricity bill was 4.2 kW-h less than 20% of this month's bill.**