For true altitude altimeter will be set to 1003 which is the sea level pressure given. so 1013-1003=10*30=300 ft under-reading when set to SLP.
true altitude under standard temp conditions would be 16000-300=15700ft
ISA temp at FL 160=15-32=-17 degrees.Given OAT= -27 degrees which is 10 degrees lower than standard temp.
we know,for every 10 degree warmer atmosphere from standard,we add 4% of indicated to get true altitude. In this case its 10 degrees colder so we will subtract 4%of 15700=628ft under reading
so true altitude 15700-628=15072ft.
P.S.-Though I m not very sure,but acc to me this should be the probable solution to this question.Cheers!!!