Philip

Philip is snorkeling along a coral reef. He's wearing an altimeter, which tracks his elevation. Philip snaps a picture of the reef at an elevation of -10 1/2 feet. Then he spots a nurse shark and swims to it for a closer look. By the time he reaches the shark, his elevation changes by -3 1/2 feet. What is Philip's elevation when he reaches the shark?

Correct answer:

x =  -14 ft

Step-by-step explanation:

$$\begin{gathered} a=-10\frac{1}{2}=-\frac{21}{2}=-10.5\text{ft} \\ b=-3\frac{1}{2}=-\frac{7}{2}=-3.5\text{ft} \\ x=a+b=\frac{-21}{2}+\frac{-7}{2}=\frac{-21+(-7)}{2}=\frac{-28}{2}=-14\text{ft} \end{gathered}$$

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