Given the phrase "Where NONE of the following are TRUE" and two statements how should a boolean logic be composed?
The correct meaning is: 

"Where (NOT (value > 10)) AND (NOT (value &lt; 25))".

Applying one of the De Morgan's laws: 

1) P AND Q &lt;=> NOT( (NOT P) OR (NOT Q) )
2) P OR Q &lt;=> NOT( (NOT P) AND (NOT Q) )

we get: 

"Where NOT ( (NOT(NOT(value > 10))) OR (NOT(NOT(value &lt; 25))) )"

and the equivalent final result is

"Where NOT ((value > 10) OR (value &lt; 25))" :-)