Rs 10000 monthly SIP can become Rs 5.17 lakh in 3 years, only if the annualized return is somewhere around 23%.
There are over a dozen funds which have given more than 23% annualized returns in last 3 years, with some of the funds giving 38 to 42% per annum returns.
But, it does not guarantee that the same rate of return is achieved in next 3 years. Returns varies a lot and hence may be lower or higher in future.
Anyway, the best returns are achieved by staying invested in a good fund for a long time. The longer one keeps going, the returns are better. So investment through SIP route should start as early as possible