I have a question in your Bob Tait text book
The altimeter setting used for cruise should be changed
A area QNH on leaving the cruising level on descent to b
B 1013 hpa on leaving the cruising level on descent to b
C 1013 hpa passing through the transition level on descent
D local QNH at b prior passing through FL115 on descent
2 If during cruise at FL 155 it became necessary to descend and cruise at 7500 ft the altimeter setting should be changed to
A local QNH of an aerodrome within 100nm of area QNH through FL115
B 1013 hpa on passing through FL110 on descent to 7500 ft and local QNH At b at top of descent to b
C area QNH once cruise is established at 7500ft and local QNH at b at top of descent to B
D local QNH of an aerodrome within 100nm or area QNH passing through FL110 on descent to. 7500 ft and local QNH at b at top of descent to b
3 the lowest flight level that could be planned for this flight is
A 1500ft
B 5500ft
C FL115
D FL135
If the local QNH at the destination aerodrome is less than that at the departure aerodrome which statement below is correct regarding the actual height of the aircraft above mean sea level if the pilot maintains a constant altimeter reading ?
A the aircraft would be descending during cruise at FL 155
B the aircraft would be climbing during cruise at FL 155
C the aircraft would remain at a constant height above mean sea level
D the aircrafts height above mean sea level would be greater than 15500 ft
The transition level on this flight would be
A FL115
B11000 ft above mean sea level
C FL110
D higher than 11000 ft above mean sea level
The depth of the transition layer on this flight would be
A 1000 ft
B 1230ft
C 1070ft
D 770ft

Chanejane
You will find the answers to all of those questions in ENR 1.7 para 2.1.2

Thanks Bob