To find the cost per room for the spot cleaning company, we can divide the total charge by the number of rooms cleaned. The spot cleaning company charges $300 for six rooms.
Cost per room for the spot cleaning company: \[ \frac{300}{6} = 50 \]
So, the spot cleaning company charges $50 per room.
The carpet cleaning pros charge $40 per room, which is less expensive.
Therefore, the less expensive company is the carpet cleaning pros, charging $40 per room.