The submarine is cruising at a depth of 50 meters, then dives 75 meters, then ascends (moves in the direction of the surface )60 meters, and then dives 45 meters. what is the submarine's final depth

Interesting question... let's draw a picture.

50 m
                     \               \
    75 m down \           / 60 m up      45 m down
                       

So what's going on?
Going 75 m deeper: 50 + 75
Coming up 60 m    : 50 + 75 - 60
Going 45 m deeper: 50 + 75 - 60 + 45

Final depth: 110 m
 

Bis the right answer