Amal buys $110$ kg of syrup and $120$ kg of juice, syrup being $20\%$ less costly than juice, per kg. He sells $10$ kg of syrup at $10\%$ profit and $20$ kg of juice at $20\%$ profit. Mixing the remaining juice and syrup, Amal sells the mixture at ₹308.32 per kg and makes an overall profit of $64\%$. Then, Amal's cost price for syrup, in rupees per kg, is