Output a text that doesn't output any of the characters used in the instructions to output the text
Jelly, 0 bytes, score: 1/0 = ∞


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That's right, the empty program in Jelly prints 0.
Jelly, 5 bytes, score: 1000.6
⁶³ȷ³x

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Jelly, 2 bytes, score: 95 / 2 = 47.5
ØṖ

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This yields the set of all printable ASCII: !&quot;#$%&amp;'()*+,-./0123456789:;&lt;=&gt;?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ and a space (95 bytes)