带100斤菜去 然后留下50斤 自己带50斤过去

<font size="1" face="宋体" color="navy">再多带</font><font size="1" face="Arial" color="navy">90</font><font size="1" color="navy">斤的石头过河，把石头作为酬劳！<img src="http://www.italki.com/fckeditor/editor/images/smiley/msn/teeth_smile.gif" alt="" /></font>

将九十斤菜分左右放系船既两边既水入面，利用水既浮力减轻菜既重量，所以呢个时候菜既重量肯定系小于90斤既，咁样除以2之后就会小于45，甘就可以带多过45斤既菜过去喇~<img src="/FCKeditor/editor/images/smiley/msn/wink_smile.gif" alt="" />