Based on 30 days.
5000 x 8 years = 40,000/-
5000/365*180days = 2,466/-
5000/365*15days = 205/-
Total = 42,671/-

Based on 21 days.(5000/30*21=3500)

3500 x 8 years = 28,000/-
3500/365*180 days = 1,726/-
3500/365*15 days = 144/-
Total = 29,870/-