(Refer to CAP 697 - figure 2.3)
Given:
FL75
OAT: +2° C
Wind component: -12 kts
Distance: 45 NGM
Power setting: 21 in. HG (or full throttle) @ 2100 RPM
Find the TAS, GS, Time and fuel required for this flight leg:

TAS 141 kts; GS 129 kts; 21 minutes; 3.3 gallons
TAS 141 kts; GS 129 kts; 20 minutes; 3.5 gallons
TAS 139 kts; GS 127 kts; 21 minutes; 3.3 gallons
TAS 139 kts; GS 127 kts; 20 minutes; 3.5 gallons