7.3. A trading organization wholesale purchased exotic fruits, the moisture content of which was $99\%$ of their mass. After delivering the fruits to the market, the moisture content dropped to $98\%$. By what percentage should the trading organization increase the retail price of the fruits (the price at which it will sell them to the public) compared to the wholesale price to at least cover the costs of purchasing the fruits?
Solution. In 100 kg of fresh fruits, there was 99 kg of water and 1 kg of solid mass. After drying, 1 kg of solid mass constituted $2 \%$ of the mass of 50 kg, i.e., every 100 kg of fresh fruits dried down to 50 kg, i.e., by half, and the retail price, compared to the wholesale price, should be increased by two times.

Answer: by $100 \%$.