Question

A scuba diver uses negative numbers to represent her depths below sea level. She was at a depth of -1.5 meters. A few minutes later she continued another -4.2 meters to the ocean floor below. What was her final depth? What happens when we need to combine two depths?​​ Write your expression, show your work, and label your answer.

Answer 1

a). -5.7 meters or 5.7 meters below sea level

b). When we combine the two depths we sum them since they are an increment in the same direction and we sum them from the seal level, our first reference point.

Explanation:

a). Final depth=Initial depth+deeper increment=(-1.5)+(-4.2)=-5.7

Initial depth=-1.5 represented by a negative number since she is below sea level, meaning her reference point(point 0) is the sea level. The more she moves below the sea level the deeper she goes and the more her depth becomes negative

Deeper increment=-4.1, she further moves deeper from her initial depth(-1.5) by a value of -4.1. In order to find her final depth, we have to sum all the depths she covered from her first reference point which is the see level.

The expression is;

Final depth=Initial depth+deeper increment=(-1.5)+(-4.2)=-5.7 meters

Her final depth=-5.7 meters

b). When we combine the two depths we sum them since they are an increment in the same direction and we sum them from the seal level, our first reference point.