15. Oil Change

Answer:
Using the De Morgan Rule
!(A && B) is equivalent to !A && !B
the original expression
while ( !(input.equals( "quit" ) || (count > limit)) ) 
{
   . . . 
}
is equivalent to
while ( !input.equals( "quit" ) && !(count > limit)) ) 
{
   . . . 
}
which is equivalent to
boolean reject = (speed <= 2000) || (memory <= 512)

Oil Change

The owner's manual for a car says to change the oil every three months or every 3000 miles.

boolean newOilNeeded =  months >= 3 || miles >= 3000 ; 

Here is an expression that shows when no oil change is necessary:

boolean oilOK =  !( months >= 3 || miles >= 3000 ); 

Question 15:
Rewrite the last expression using one of De Morgan's rules. Do this in two steps. In the first step, don't change the relational expressions.
boolean oilOK =           
Now further simplify by changing the relational expressions.    
boolean oilOK =