A company has an indoor pool with a natural gas water heating system. A technical-economical study was carried out for the application of solar panels for water heating, with the following data and conclusions: i. Global economy (annual) 13 500 ii. Investment 40 000 iii. Solarpaneluseful life 12years Considering that this project would receive support from a National Economy Program of 40% of the total investment,anda = 9.5%. Calculate: a) Payback b) Net PresentValue(NPV) c) Internal rate of return(IRR).