设商店永生金笔X支，则英雄金笔143-X支，设购买的永生金笔是该商店永生金笔的百分数为Y，总价=X*Y*6+（143-X)*3.78=6*X*Y+540 .54-X*3.78=(6*Y-3.78)X+540.54由题意知，总价和X无关，所以6*Y-3.78=0Y=3.78/6=63%总价=540.54购买的永生金笔是该商店永生金笔总数的63%应付款的总数是540.54元
