2个梨=4根香蕉,则1个梨=2根香蕉
4根香蕉=2个桃子+1个梨+1根香蕉
4根香蕉=2个桃子+2根香蕉+1根香蕉=2个桃子+3根香蕉
1根香蕉=2个桃子=0.3*2=0.6千克
1个菠萝=4根香蕉=0.6*4=2.4千克