To paint a room, Pretty Paint company charges $75 per room. Big Bucket Paint Company charges $426 to paint a 6 room house. List the cost per room of the least expensive company.

To find the cost per room of the least expensive company, we need to determine the cost per room for each company.

For Pretty Paint Company:
Cost per room = $75

For Big Bucket Paint Company:
Total cost to paint a 6 room house = $426

Cost per room = Total cost / Number of rooms
Cost per room = $426 / 6 = $<<426/6=71>>71

Comparing the cost per room for both companies, we can see that the Pretty Paint Company charges the least expensive rate at $75 per room.