There are 50 kinds of known apples.

* * * 50 fruit trees (1-1/3-1/4) =120.

Analysis: Apple accounts for1-1/3-1/4 = 5/12, and there are 50 apples.

2、

It is known that pear trees are less than peach trees 10.

There are10 ÷ (1/3-1/4) =120 fruit trees.

Analysis: pear trees are less than peach trees1/3-1/4 =112, and there are 10 trees.

So there are10 ÷112 =120 trees in total.