17 trees are pine while 40-17 = 23 are not pine.
23/40 = 0.575 = 57.5% of the trees are not pine trees.
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Another way to get the answer:
17 pine out of 40 total
17/40 = 0.425 = 42.5% of the trees are pine trees.
100% - 42.5% = 57.5% is the final answer.
