At the age of 15, Einstein felt so stifled that he left the school for good, (permanently, for his benefit, for a short time)

After passing his secondary school examination, David left the school at the age of 15 yers and started getting training his father. His father, a renowned electrician, had worked for many companies. He eveeryday started accompanying his father on work quickly. Now his father started passing on the tricks of the trade to David. With the passage of time David acquired a high lavel skill and became a well-known electrician at Indore. Big business-houses started callin him for electrical-wiring. (a) Name the method of training discussed in the above para. (b)State any three benefits which David could get on being trained.