Answer:
-13° C
Explanation:
Data provided:
The temperature of the air at sea level = 26° C
The height at which temperature is to be calculated = 6000 m = 6 Km
Now,
Using the average lapse rate

Here,
is the temperature at the height 'h' above the mean sea level
is the temperature at the mean sea level
is the average lapse rate = 6.5° C per Km
h is the height above mean sea level at which the temperature is to be calculated in Km
on susbtituting the respective values in the above formula, we get
= 26° C - ( 6.5 × 6 )
or
= 26° C - 39° C
or
= -13° C