To find the total cost of carpeting, we started with the equation you derived:
\[ c = 100r + 50 \]
where:
- \( c \) represents the total cost,
- \( r \) is the number of rooms,
- \( 100 \) is the cost per room, and
- \( 50 \) is the flat installation fee.
Now, to determine the cost for 4 rooms (\( r = 4 \)), we substitute \( 4 \) for \( r \) in the equation:
\[ c = 100(4) + 50 \]
Now we calculate it step-by-step:
- Multiply \( 100 \) by \( 4 \):
\[ 100 \times 4 = 400 \]
- Add the installation fee of \( 50 \):
\[ 400 + 50 = 450 \]
So, the total cost to have 4 rooms carpeted by Flooring City would be:
\[ c = 450 \]
Thus, the total cost for carpeting 4 rooms is $450.