the 15-15-15 method of becoming a millionaire / crore-pati states that
you need to invest 15,000 per month
for 15 years
at an annual interest rate of 15 %
to become a crore-pati
you can feed the parameters at the following link
https://www.thecalculatorsite.com/finance/calculators/compoundinterestcalculator.php