Altitude above sea level is given in positive values and below sea level is given in
negative values. Which situation describes a hiker in Death Valley stopping at an
altitude of O feet? (If you are stuck, draw a number line).
a. The hiker starts at -10 feet then increases altitude by 10 feet.
b. The hiker starts at -10 feet then decreases altitude by 10 feet.
c. The hiker starts at 10 feet then increases altitude by 10 feet.
d. The hiker starts at 0 feet then decreases altitude by 10 feet.