买45千克葡萄和10千克香蕉共付47.80元,后来退回10千克香蕉换成15千克葡萄,又付7.40元,1千克葡萄比1千克香蕉的价钱多多少元?
问题描述:
买45千克葡萄和10千克香蕉共付47.80元,后来退回10千克香蕉换成15千克葡萄,又付7.40元,1千克葡萄比1千克香蕉的价钱多多少元?
答
(47.8+7.4)÷(45+15)
=55.2÷60
=0.92(元)
(47.8-0.92×45)÷10
=(47.8-41.4)÷10
=6.4÷10
=0.64(元)
0.92-0.64=0.28(元)
答:1千克葡萄比1千克香蕉的价钱多0.28元.