（78.6-0.786×25十75%×21.4）÷15×2011
=（78.6-78.6×0.25+75%×21.4）÷15×2011，
=[（1-0.25）×78.6+0.75×21.4]÷15×2011，
=[0.75×78.6×0.75×21.4]÷15×2011，
=（78.6+21.4）×0.75÷15×2011，
=100×0.75÷15×2011，
=75÷15×2011，
=5×2011，
=10055．
故答案为：10055．