何智强
幼苗
共回答了23个问题采纳率:95.7% 举报
是问怎么分配最省钱是吧?
设租大车x辆,租小车y辆(x、y都为整数).
所以总费用Z=1000x+650y.
40x+25y大于等于275.
在x、y坐标轴上画出:1000x+650y=0和40x+25y=275的直线方程,两方程必有一个交点,如果交点横纵坐标为整数即为x、y的数值,若不是(本题估计就不是),就要去这个交点最近的两个整数做标点带入Z=1000x+650y的方程,看谁最小就最省.
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设小明x岁,则小明的妈妈是x+28岁,又因为小明妈妈的年龄是小明的5倍,所以x+28=5x.
得出x=7岁,他妈35岁.
1年前
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