Question 69959
The water level of a reservoir is measured over a five month period at the beginning, the level is 25 ft, during this time, the level fell 3 ft, then rsoe 1 ft, then fell 4 ft, and then rose 2 ft. What is the reservoirs water level at the end of 5 months. 
:
Plus + means rise; Minus (-) means fall
:
Just do the math:
25 - 3 + 1 - 4 + 2 = 21 ft