#### Answer

a). $-51.5^{\circ}C$
b). $-47.3^{\circ}C$

#### Work Step by Step

Let us assume that room temperature $=20^{\circ}C$
a). So, temperature near top of troposphere = $20^{\circ}C-6.5\times11^{\circ}C=-51.5^{\circ}C$
b). altitude = 34000ft=10.36kms
required temperature =$20^{\circ}C-10.36\times6.5^{\circ}C=-47.3^{\circ}C$