On the CRP5 low speed side put the wind in, 250/20kts
with the wind speed underneath the centre dot. Next put the centre dot under
the TAS 105kts. Rotate to read 035o under the true heading and
you'll see there is 5o right drift. Rotate 5 degrees to the right to
read 030o under the true heading and you'll read off a speed of
122kts. so your outbound speed is 122kts. Next you need the speed of your
return leg, 180 + 035 = 215o.
Put this under the true heading and you'll see 7o
of left drift, so rotate the cursor 7o towards to dot and you'll
have 208 o under the true heading, and read of a speed of 91 kts.
This is your homeward bound speed.
The question asks for PSR which is dependent on endurance so we use this. In this case, 3.5 hrs.
So from the formula E x H / O + H, I get a time of 1.068 hrs. Multiply this by
the outbound speed (122 kts) and the distance is 130nm.