My ATPL notes suggest adding 4% for every 10 degrees below ISA. This gives an answer of 10% for ISA-25 - the same answer as quid got from his chart.
I also agree on the second one. The temperature is ISA-40, so you need to add 16% to the actual altitude to get the indicated altitude - 2042'. That's assuming that the temperature remains at an average of ISA-40 all the way up to your altitude, of course - the question doesn't specify this.
[Edit - actually, re-reading the question, the OAT is -25. This implies that -25 is the temperature at 1760', where ISA is 11.5 degrees, not 15 degrees. But even with that correction, I still can't get any of the suggested answers.]
FFF
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Last edited by FlyingForFun; 6th September 2002 at 13:10.