设原来共有X个
X-(5X/9-3)+31=X+20%X
4X/9+34=1.2X
34X/45=34
X=45
原来有45个苹果
原来小明买来9X个苹果,吃了全部的5/9少3个=9X*(5/9)-3=5X-3剩下9X-(5X-3)=4X+3
=> 4X+3+31=9X *1.2 => 6.8X=34 =>X=5 =>9*5=45 .....ANS
原来苹果*1.2倍-31=原来苹果的4/9多3
=> 34÷(6/5 - 4/9)=45...ANS
设原来共有X个
X-(5X/9-3)+31=X+20%X
4X/9+34=1.2X
34X/45=34
X=45
原来有45个苹果