How are you supposed to get the East/West variation on this question in the FAA PPL written exam? While taking a practice test, I needed to calculate the magnetic heading between two airports. Most of the time I run into a problem, the map will provide me with isogonic lines with the East/West variation visible. But in at least one or more questions, the isogonic line is either not shown, or the numbers are not visible.

Using the protractor to calculate the angle on the isogonic line using the latitude/longitude lines doesn't seem to give me the correct number either. 

Does anyone know what I am doing wrong or how I can come to a correct answer?

Problem

(Refer to figure 23.) What is the estimated time en route for a flight from Claxton-Evans County Airport (area 2) to Hampton Varnville Airport (area 1)? The wind is from 290° at 18 knots and the true airspeed is 85 knots. Add 2 minutes for climb-out.

Valid Answers:


44
39
35




Update: I added an actual sample problem. Assuming the only information I am able to work with is the map, the question and my E6B (manual or electronic).

Update
I found the original question that got this thread started:

(Refer to figure 24.) Determine the magnetic heading for a flight from Allendale County Airport (area 1) to Claxton-Evans County Airport (area 2). The wing is from 090° at 16 knots, and the true airspeed is 90 knots.

The correct answer: 209°

The solution given in study mode: With a plotter, measure the true course from Allendale to Claxton-Evans as 212°. Use a flight computer to find the true heading of 203°. Add variation of 6°W. 203°+6°=209°.
Real answer: The FAA screwed up in preparation of that exam question (this sometimes happens; they aren't perfect) and cropped the sectional to where the isogonal lines and or isogonal values are not visible.  As it happens I know that area of the country pretty well.

It works out that Claxton has about a 6.5 deg W magnetic variation (get the full VFR sectionals for that area) and Varnville is just shy of 7deg  W variation; I'd use 6.75 deg W as your number for mag variation over the duration of the flight.  That works out to a course of 051 deg magnetic, 56.5 NM along the route.  With winds at 290 at 18 kts cruising at a true airspeed of 85 kts, this gives an aircraft heading of 041 magnetic in cruise with a ground speed of 93 kts.

Now here's the thing: what is your groundspeed during climb out?  That's going to also be necessary to calculate how much ground you cover during your 2 min climb to cruise. And critical to answering the question correctly.

Now, IF WE ASSUME a constant groundspeed of 93 kts, from point to point, that gives a flight time of 36.5 minutes.  If we further assume the two minutes of climb are not enroute and just maneuvering from takeoff to on course right over the Claxton airport and we descent into Varnville at 93 kts as well, we get a figure of 38.5 minutes total flight time.  Therefore, I'd select 'B' as my answer.

As a side note, I landed an LSA out at Varnville only once and that place is virtually abandoned; it was difficult to identify as an airport from the air, the runway is anemic and derelict, there are virtually no buildings there and all I could find for traffic there was a decrepit C-150 rusting in the sun.  I took off again - and very glad my engine didn't quit, leaving me stranded there.