It is assumed that a country's net terms of trade would be 100 for the base period of 2010. In 2010, the export commodity price was 50 yuan. In 2015 it was 40 yuan, In 2010, the import commodity price was 150 yuan, and in 2015 it was 165 yuan. (1) What is the country's net terms of trade for 2015? (2) If the country's export volume rose by 50 % from 2010 to 2015, what are the terms of trade for income?