A trainee receives a monthly stipend that increases by a fixed amount each month. The stipend for the first month is ₹10,000 and the total stipend received during the first 12 months is ₹1,86,000.
(i) Calculate the monthly increment in the stipend.
(ii) In which month will the stipend first exceed ₹20,000?
(iii) Find the total stipend that the trainee will receive in the first 18 months.