A vendor purchased 40 dozens bananas for Rs250. Out of these 30 bananas were rotten and could not be sold. At what rate per dozen should he sell the remaining bananas to make a profit of 20%.

Cost price of 480 (40*12) bananas = Rs. 250

Number of bananas sold = 480-30=450

Selling price of 450 bananas = Cost price + profit = 250 + 20%of 250 = 250+50 = Rs. 300

Selling price of 12 bananas =

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