you need to obtain housing for 42 people, you can house only 4 people per room. how many rooms do you need

Question

number system

Answer 1

With 4 people in a room, the rooms would look like:

    4    4    4    4    4    4    4    4    4    4    2   =   42

or

    4    4    4    4    4    4    4    4    4    3    3   =   42

 

Any other numbers would take more rooms.  So, this is the fewest number of rooms.  How many are there?