Answer:
11.6m
Explanation:
Given Ben is at 15.8 metres below the surface of water
Also given that Cam is 4.2 meters above ben
The position of Cam with respect to the surface of the water = The position of Ben with respect to the surface of the water - The position of Cam with respect to Ben
Given The position of Ben with respect to the surface of the water = 15.8m
The position of Cam with respect to Ben = 4.2m
The position of Cam with respect to the surface of the water = 15.8 - 4.2 = 11.6m