A tenant pays a monthly house rent of ₹8,000 during the first year. The rent is fixed to rise by ₹500 at the beginning of each subsequent year.
(i) Find the monthly rent payable during the 15th year.
(ii) Compute the total rent paid over the first 15 years.
(iii) After the 15th year, the landlord refunds ₹10,000 to the tenant as a special concession. Determine the effective average monthly rent paid by the tenant over the 15-year period after accounting for this refund.