A submarine is at a depth less than 40 feet below sea level. Which sentence is true? A. The submarine must rise more than 40 feet to reach sea level.
B. The submarine must rise exactly 40 feet to reach sea level.
C. The submarine can reach sea level by rising less than 40 feet.
D. If the submarine rises exactly 40 feet it will be above sea level.

1 number

if we use a graphing calculator, there is only one such number that satisfies the conclusion of the mean value theorem, that is, a number such that

where the right-hand side is the average rate of change of f on the interval [0.5,0.75], which is the slope of the secant line.

in the attached graph, the black line is the secant line which has its slope as the average rate of change of f on [0.5,0.75], while the orange line is the only tangent line to the graph of f in the interval that satisfies the mvt conclusion.