Mom gave Xiaoqing 11.1 yuan to buy 5 catties of bananas and 4 catties of apples, but the quantity he bought was reversed, leaving 0.6 yuan. So how much is the price of apples per catty?
妈妈给小青11.1元，让他去买5斤香蕉、4斤苹果，结果他买的数量给弄颠倒了，从而还剩下0.6元．那么苹果每斤的售价是多少元．
<result>0.9</result>