Practice Test 7

A science class records water temperature changes. The water starts at $-2.5^\circ\text{C}$. The teacher warms it by $7\tfrac{1}{2}^\circ\text{C}$, then a student adds ice that lowers the temperature by $\tfrac{3}{4}^\circ\text{C}$. What is the final temperature?

A hiker starts at an elevation of $450\text{ m}$ above sea level. The trail goes down $275\text{ m}$, then up $180\text{ m}$, then down another $\tfrac{1}{2}$ of $60\text{ m}$. What is the hikers final elevation?