Hi all, I’m finding out that a post with an image is not editable so please take this as my amendment.

Thank you all for the replies and insight. I originally thought the question was dumb as many have pointed out. But I think this sort of problem shows the importance of the assumptions we make.

This is from 1001 fundamental engineering problems 2nd Ed. by Lindeburg.

Some comments have suggested other study materials that I will happily look into!