Table 2.2.3 ....
there are 3 parts to the table ... in terms of Temperature condition, the table
gives 'ISA Deviation' ... 'ISA -20ºC'. ISA, and 'ISA +20º'.
So, for this question we are at FL
75, ISA at this level is 0ºC, so with OAT +10ºC, we are 10ºC warmer than ISA,
so the ISA Deviation is 'ISA +10ºC' ..... therefore,
to answer the question, we need to interpolate between the 'ISA' and 'ISA
+20ºC' sections of the table.