40 percent of Andrea's living room floor is covered by a carpet that is 4 feet by 9 feet. What is the area of her living room floor?

Answer

To find the area of Andrea's living room floor, we can follow these steps:

### Step 1: Define the area of the living room floor
Let the area of Andrea's living room floor be denoted as \( X \).

### Step 2: Calculate the area of the carpet
The area of the carpet can be calculated using the formula for the area of a rectangle, which is:
\[ \text{Area} = \text{Length} \times \text{Breadth} \]
Given that the dimensions of the carpet are 4 feet by 9 feet, we can calculate:
\[ \text{Area of carpet} = 4 \text{ feet} \times 9 \text{ feet} = 36 \text{ square feet} \]

### Step 3: Set up the equation based on the percentage covered
We know that 40% of the living room floor area is covered by the carpet. Therefore, we can express this as:
\[ 0.40 \times X = \text{Area of carpet} \]
Substituting the area of the carpet we calculated:
\[ 0.40 \times X = 36 \]

### Step 4: Solve for \( X \)
To find \( X \), we can rearrange the equation:
\[ X = \frac{36}{0.40} \]
Calculating this gives:
\[ X = \frac{36 \times 100}{40} = \frac{3600}{40} = 90 \]

### Step 5: Conclusion
Thus, the area of Andrea's living room floor is:
\[ \text{Area of living room floor} = 90 \text{ square feet} \]

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