How would you use the mental clock code to solve this dead reckoning problem?
Step 1: Calculate maximum drift.
Max drift $ = \frac{wind speed}{TAS (NM/min)} = \frac{24}{120/60} = \frac{24}{2} = 12$
That means if you have a direct crosswind, you'll need to correct 12$^{\circ}$.
Step 2: Determine how much of the wind is crosswind
The mental clock code is a way of estimating crosswind component from total wind. There are 60 minutes on a clock face.  If the wind direction is 60$^{\circ}$ or more, it's considered all crosswind, just as 60 minutes is considered the whole clock face.
By extension, a wind angle of 30$^{\circ}$ means 30 minutes, which is half a clock, so half the wind would be considered crosswind.  15 degrees would be a quarter of a clock, therefore a quarter of the wind, and so on.
Your maximum drift is 12 degrees with a full crosswind, but you don't have a full crosswind. Instead you have a 45$^{\circ}$ angle, so 45 minutes of a clock, which is $\frac{3}{4}$.
$ 12 * \frac{3}{4} = 9$ so you'll need to apply 9 degrees of crosswind correction toward the wind.  $270 - 9 = 261^{\circ}$
Step 3: Correct for variation
&quot;East is least, West is best&quot;.  If variation is west, add to true to get magnetic.
$261 + 4 = 265^{\circ}$