Based on the information given the amount of the device in total is £360.
Using this formula
Total cost=Cost price+(Cost price× Value added tax)
Where:
Cost price=£300
Value added tax=20%
Let plug in the formula
Total cost=£300+(£300×20%)
Total cost=£300+£60
Total cost=£360
Inconclusion the amount of the device in total is £360.
Learn more about value added tax here:https://brainly.com/question/20392481