Tata Tea today made an open offer to purchase an additional 20% stake in Mount Everest Mineral Water (MEMW) for Rs 95.19 crore.The Tata group firm will acquire up to 67.99 lakh equity shares at a price of Rs 140 each, to be funded through internal accruals, the company said in a public announcement.DSP Merrill Lynch is the manager to the public offer.On June 1, Tata Tea agreed to buy 25.74% stake in Mount Everest for around Rs 115 crore through subscription of preferential shares from promoters of MEMW. It said it would acquire another 20% later.