Refer to figures. 
Note: This question gives an answer of 68.5 NM only if an exact groundspeed of 104 kt is used. However, based on different calculations, the actual groundspeed lies between approx.103 kt and 104 kt (around 103.4 kt – 103.7 kt). When using a flight computer, this may be rounded to either 104 kt or 103 kt; in both cases, the answer is close to 68.5 NM.

CALCULATE THE GROUNDSPEED
We can use a flight computer (CRP-5) to calculate the groundspeed using the following steps:
However, since the wind is forecast, it is given in True direction. As the course is in Magnetic direction, it must first be converted to True. Therefore,

• Using the mnemonic, “VARIATION WEST → MAGNETIC BEST”.
• True Course: 205°(M) - 15°W = 190°(T)

Steps 1 - 3 (Figure 1)

1. Set the center to your True Airspeed (TAS) of 125 kt.
2. Bring wind direction of 240° under the “TRUE HEADING”.
3. Mark a dot at the wind speed of 30 kt BELOW the center, at 95 kt.

Steps 4 - 7 (Figure 2)

4. Bring true course of 190° under the “TRUE HEADING”.
5. This value will result in a drift of 12° L (-).
6. Increase value under “TRUE HEADING” by 12° so that the difference between HDG and drift results in a TRK of 190°. This is achieved at a HDG of 202°.
7. Read the drift of 10.5° L (-) and a Groundspeed (GS) of 103.5 kt ~ 104 kt.

CALCULATE THE NAUTICAL AIR MILES (NAM)
Using formula:

• NAM = NGM x TAS / GS
• NAM = 57 NGM x 125 kt / 104 kt
• NAM = 68.5 NAM