回复：数学家见了就傻的买菜问题

here is the answer.

X+Y+Z=100
3X+3/2Y+1/5Z=100
1.6X+0.59Y+1.21Z=100
解方程，答案如下：
胡萝卜=9.942041908 (10斤)= 30 个
茄子=40.12483281 (40斤)=60个
南瓜=49.93312528 (50斤)=10 个

cost: 10X1.6+40X0.59+1.21X50=100.1 元

0.1 元 deficit, the clerk just waive it.