1. Find the payback period of a 5 years project, if initial investment Rs650 cr and each year PBT is Rs189 cr, tax rate 20% and same depreciation amount over the 5 years.

Answer is 2.4 but I need the process?

2. What is the IRR of the project, if initial investment is $500 million at WACC rate of 10% and yearly cash flow after tax for next six years amounted to be $112 million each year?

Answer is 9.2 % but how?