To determine how many office buildings can be washed, we can set up an equation based on the information given.
Let \( x \) be the number of office buildings cleaned. Each office building has enough supplies to clean 21 windows, and there is also one school with 42 windows. The total number of windows that can be cleaned is 126.
Setting Up the Equation
Given that:
- Windows cleaned per office building = 21
- Windows cleaned for the school = 42
- Total windows cleaned = 126
We can represent the total number of windows cleaned with the following equation:
\[
21x + 42 = 126
\]
Where:
- \( 21x \) represents the total number of windows from \( x \) office buildings.
- \( 42 \) represents the windows of the school.
- The sum equals the total number of windows, which is 126.
Solving for \( x \)
-
Subtract 42 from both sides:
\[
21x + 42 - 42 = 126 - 42
\]
\[
21x = 84
\]
-
Divide by 21:
\[
x = \frac{84}{21}
\]
\[
x = 4
\]
Conclusion
So, the number of office buildings that can be cleaned is 4.
Summary of the Equation
The equation that can be used to solve this problem is:
\[
21x + 42 = 126
\]
This equation represents the relationship between the number of office buildings and the total number of windows cleaned.