A person deposits money in a bank at the end of each week. He deposits ₹600 in the first week and increases the deposit by ₹50 every subsequent week.
(i) Find the amount deposited in the 20th week.
(ii) Calculate the total amount deposited at the end of 20 weeks.
(iii) If the same pattern continues up to the 30th week, determine the total amount deposited from the 21st week to the 30th week only.