Need some help with a seemingly simple question
Try this: (a small amount of rounding, not considering instrument error -basic)

Speed = Distance x 60/Time (in minutes)

Speed = 155 x 60/83(minutes)

Speed = 112 nmh

Speed of 112 nmh consists of 100 kts TAS and 12 kts Tailwind.

Then, TAS = 100 kts.