Question

A submarine is 50 m below sea level. It goes down a further 280 m to sit on a rock. What is the depth of the rock below sea level?

• A. - 330 m
• B. - 50 m
• C. - 280 m

Answer 1

The correct option is A - 330 m

Convention:

• At the sea level, Distance is considered a zero level.
• Distance below sea level is considered as negative.
• Distance above sea level is considered as positive.

Initial position of submarine is 50 m below sea level $\Rightarrow$ - 50 m
The submarine goes further 280 m down to sit on a rock.

Final position of submarine
= $(-50)-280$ m

Using number line,


$(-50)-280=-330$ m

$\therefore$ The final position of the submarine is $-330$ m.