Shawn and ellie are construction workers. shawn can complete a concrete job in 4 hours, while ellie can complete it in 6 hours. the foreman says that it will take them 5 hours to complete it if they work together. explain each step in solving this equation, and determine if the foreman is correct or not.

3 is greater then both of those numbers

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.