Major averages kicked off the week with solid gains after China took more steps to stimulate its economy. By the close, the Nasdaq added 1.3%, the Dow Jones industrial average rose 1.2% and the S&P 500 picked up 0.9%. Preliminary data showed NYSE and Nasdaq volume coming in much lower than Friday, but volume was heavy Friday due to options expiration. Advancing stocks had the upper hand over decliners by more than 2-to-1 on both exchanges.