A king ordered to make a crown from 8 kg of gold and 2 kg of silver. The goldsmith took away some amount of gold and replaced it by an equal amount of silver and the crown when made, weighed 10 kg. The king knows that under water gold loses 1/20th of its weight, while silver loses 1/10th. When the crown was weighed under water, it was 9.25 kg. How much gold was stolen by the goldsmith?