(1)应付款=10*y+20*(x-y)
(2)47个成人以团体名义购票,花费47*20*0.8=752元; 学生购买学生票12*10=120;总共花费972元
楼上错误752加120等于872!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!