What annual payment will discharge a debt of Rs. 580 due in 5 years, the rate being 8% per annum?

Let the annual installment be Rs. P
Then, [P + (P x 4 x 8)/100] + [P + (P x 3 x 8) / 100] + [P + (P x 2 x 8)/100 ] + [ P + (P x 1 x 8)/100] + P = 580
⇒ 33P/25 + 31P/25 + 29P/25 + 27P/25 + P = 580
⇒ (120 + 25)P = 580 x 25
∴ P = 100