Refer to figure.
The 1-in-60 rule can be used to calculate the total heading correction required to regain the desired track.

Calculate the Track Angle Error (TKE)
The track you want to fly is the planned track, and the track you actually make over the ground is the track made good (actual track). The difference between the planned track and the track made good is called Track Angle Error (TKE).
Step 1: Calculate the distance along track

• Distance along track is the distance flown along the intended track, which in our case is: 36 NM.

Step 2: Calculate the track error angle (TKE)
Distance off track is the distance by which you have deviated from your intended track. In this case, we are 3 NM right of track.

• TKE = (distance off track x 60) / distance along track
• TKE = (3 NM x 60) / 36 NM
• TKE = 5°

Turning the aircraft by 5° to the left will bring us parallel to our intended track. However, since we need to rejoin it, another correction must also be calculated.

Calculate the Closing Angle (CA)
The angle at which we want to close to come back to the planned track is the closing angle (CA). The CA depends on how far ahead we intend to rejoin the track. Since the question does not explicitly specify when we want to rejoin the track, we will assume it is at the remaining distance (i.e., the distance to go).
Step 1: Calculate the distance to go
We have covered 36 NM out of a total distance of 110 NM. Therefore,

• Distance to go (NM) = Total distance (NM) - distance flown (NM)
• Distance to go = 110 NM - 36 NM
• Distance to go = 74 NM

Step 2: Calculate the closing angle (CA)

• CA = (distance off track x 60) / distance to go
• CA = (3 NM x 60) / 74 NM
• CA = 2.43° ~ 2°

Determine the change of heading
Therefore, we should change our heading by: TKE + CA = 5° + 2° = 7° to the left