应该是有几个
0.25*4.8+0.75*4.8=(0.25+0.75)*4.8=4.8
0.25*4.8+1.75*4.8=(0.25+1.75)*4.8=2*4.8=9.6
0.25*4.8+2.75*4.8=(0.25+2.75)*4.8=3*4.8=14.4
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应该是有几个
0.25*4.8+0.75*4.8=(0.25+0.75)*4.8=4.8
0.25*4.8+1.75*4.8=(0.25+1.75)*4.8=2*4.8=9.6
0.25*4.8+2.75*4.8=(0.25+2.75)*4.8=3*4.8=14.4
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