The ratio of chairs to tables in an office is 9 : 7. If there are 42 more chairs than tables, find the number of chairs in the 9 office.

Options

A. 189
B. 215
C. 147
D. 200

Answer

To solve the problem step by step, we can follow this approach:

### Step 1: Understand the given ratio
The ratio of chairs to tables is given as 9:7. This means for every 9 chairs, there are 7 tables.

### Step 2: Define variables based on the ratio
Let the number of chairs be represented as \( 9x \) and the number of tables as \( 7x \), where \( x \) is a common multiplier.

### Step 3: Set up the equation based on the additional information
We know that there are 42 more chairs than tables. Therefore, we can write the equation:
\[ 9x = 7x + 42 \]

### Step 4: Solve for \( x \)
To find \( x \), we can rearrange the equation:
\[ 9x - 7x = 42 \]
\[ 2x = 42 \]
Now, divide both sides by 2:
\[ x = 21 \]

### Step 5: Calculate the number of chairs
Now that we have the value of \( x \), we can find the number of chairs:
\[ \text{Number of chairs} = 9x = 9 \times 21 = 189 \]

### Conclusion
The number of chairs in the office is **189**.

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