The marked price of every item being sold by a wholesaler was ₹300. The wholesaler was offering a stock-clearance sale under which, for every three items paid for, one item was being given free. In addition to this, a further 10% discount on the amount payable on the ‘Buy 3, Get 1 free’ scheme price was being offered to anyone making purchases worth more than ₹10,000. Ramesh made purchases for which this amount payable was ₹18,000. What was the effective percentage discount that was offered to Ramesh during this transaction?