Question

Word problem issues -
"The sub descended at a 48 degree angle for 2 kilometers"

Answer 1

I would interpret it as shown

The angle of descent is betweent he horizontal and the track taken.
'For 2 km' means (in my interpretation) 'for a distance travelled of 2km'

In the absence of words such as 'to a depth of 2km' I think this is the best option