25. A shopkeeper mixes two varieties of tea, one costing Rs. 35 per kg and another at Rs. 45 per kg in the ratio 3:2 If he sells the mixed variety at Rs. 41.60 per kg, his gain or loss per cent is:

26. If I purchased 11 books for Rs. 10 and sold all the books at the rate of 10 books for Rs. 11, the profit per cent is:

27. By selling 36 oranges, a vendor loses the selling price of 4 oranges. His loss per cent is: