You must mean the depth of the submarine.
to make sum = zero the depth of the sub must be -1600 ft..
12/6x its 2x your anwser would be 2x its simple
First term, a
1
=4
Second term, a
2
=8
Common difference, d=a
2
=a
1
d=8−4=4
∴ The common difference is 4
It is proportional because we increase y.
23% is the answer i believe
