Please describe the way to find the answer for the following question.

This problem is based on inclusion exclusion principle

50 cars were assembled in a factory. The options available were radio, AC,

power steering. It is known that 20 of the cars have radios, 12 of them have

AC and 10 of them have power steerings. 5 of them have all three options.

Determine at least how many cars do not have any options at all.